dev-lang/python/python-2.7.15.ebuild - third_party/overlays/chromiumos-overlay - Git at Google

 # Copyright 1999-2018 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 # $Header: /var/cvsroot/gentoo-x86/dev-lang/python/python-2.7.10.ebuild,v 1.2 2015/06/29 17:26:27 floppym Exp $

 EAPI="5"
 WANT_LIBTOOL="none"

 inherit autotools eutils flag-o-matic multilib pax-utils python-utils-r1 toolchain-funcs multiprocessing

 MY_P="Python-${PV}"
 PATCHSET_VERSION="2.7.15"

 DESCRIPTION="An interpreted, interactive, object-oriented programming language"
 HOMEPAGE="https://www.python.org/"

 # The version of Python our PGO profile was generated with. Using ${PV} makes
 # updates difficult, and we have tricks below to catch a mismatched profile
 # version.
 PROF_VERSION="2.7.15"

 SRC_URI="https://www.python.org/ftp/python/${PV}/${MY_P}.tar.xz
 	https://dev.gentoo.org/~floppym/python/python-gentoo-patches-${PATCHSET_VERSION}.tar.xz
 	pgo_use? ( gs://chromeos-localmirror/distfiles/python-${PROF_VERSION}-pgo-prof.profdata.tar.xz )"

 LICENSE="PSF-2"
 SLOT="2.7"
 KEYWORDS="*"
 IUSE="-berkdb bluetooth build doc elibc_uclibc examples gdbm hardened ipv6 pgo_generate +pgo_use libressl +ncurses +readline sqlite +ssl +threads tk +wide-unicode wininst +xml"

 REQUIRED_USE="pgo_generate? ( !pgo_use )"

 # Workaround: re-emerging this after emerging a `pgo_generate` Python gives us
 # a really bad time, since we'll try to write to profiles in "restricted"
 # places somehow. Specifying this profile file has LLVM write profiles to
 # /dev/null, which is always available.
 export LLVM_PROFILE_FILE="/dev/null"

 # Do not add a dependency on dev-lang/python to this ebuild.
 # If you need to apply a patch which requires python for bootstrapping, please
 # run the bootstrap code on your dev box and include the results in the
 # patchset. See bug 447752.

 RDEPEND="app-arch/bzip2:0=
 	>=sys-libs/zlib-1.1.3:0=
 	virtual/libffi:=
 	virtual/libintl
 	berkdb? ( || (
 		sys-libs/db:5.3
 		sys-libs/db:5.1
 		sys-libs/db:4.8
 		sys-libs/db:4.7
 		sys-libs/db:4.6
 		sys-libs/db:4.5
 		sys-libs/db:4.4
 		sys-libs/db:4.3
 		sys-libs/db:4.2
 	) )
 	gdbm? ( sys-libs/gdbm:0=[berkdb] )
 	ncurses? ( >=sys-libs/ncurses-5.2:0= )
 	readline? ( >=sys-libs/readline-4.1:0= )
 	sqlite? ( >=dev-db/sqlite-3.3.8:3= )
 	ssl? (
 		!libressl? ( dev-libs/openssl:0= )
 		libressl? ( dev-libs/libressl:0= )
 	)
 	tk? (
 		>=dev-lang/tcl-8.0:0=
 		>=dev-lang/tk-8.0:0=
 		dev-tcltk/blt:0=
 		dev-tcltk/tix
 	)
 	xml? ( >=dev-libs/expat-2.1 )
 	!!<sys-apps/portage-2.1.9"
 # bluetooth requires headers from bluez
 DEPEND="${RDEPEND}
 	bluetooth? ( net-wireless/bluez )
 	virtual/pkgconfig
 	>=sys-devel/autoconf-2.65
 	!sys-devel/gcc[libffi(-)]"
 RDEPEND+=" !build? ( app-misc/mime-types )
 	doc? ( dev-python/python-docs:${SLOT} )"
 PDEPEND=">=app-eselect/eselect-python-20140125-r1"

 S="${WORKDIR}/${MY_P}"

 pkg_setup() {
 	if use berkdb; then
 		ewarn "'bsddb' module is out-of-date and no longer maintained inside"
 		ewarn "dev-lang/python. 'bsddb' and 'dbhash' modules have been additionally"
 		ewarn "removed in Python 3. A maintained alternative of 'bsddb3' module"
 		ewarn "is provided by dev-python/bsddb3."
 	else
 		if has_version "=${CATEGORY}/${PN}-${PV%%.*}*[berkdb]"; then
 			ewarn "You are migrating from =${CATEGORY}/${PN}-${PV%%.*}*[berkdb]"
 			ewarn "to =${CATEGORY}/${PN}-${PV%%.*}*[-berkdb]."
 			ewarn "You might need to migrate your databases."
 		fi
 	fi
 }

 src_prepare() {
 	# According to the comments at the top of cgi.py, Linux vendors need to
 	# patch the shebang in cgi.py. We'll ignore the comment about not using
 	# "/usr/bin/env python" and use it anyway.
 	sed -i -e '1 s:^#!.*$:#! /usr/bin/env python:' Lib/cgi.py || die

 	# Ensure that internal copies of expat, libffi and zlib are not used.
 	rm -r Modules/expat || die
 	rm -r Modules/_ctypes/libffi* || die
 	rm -r Modules/zlib || die

 	if tc-is-cross-compiler; then
 		local EPATCH_EXCLUDE="*-Regenerate-platform-specific-modules.patch"
 	fi

 	EPATCH_SUFFIX="patch" EPATCH_FORCE="yes" epatch "${WORKDIR}/patches"

 	#
 	# START: ChromiumOS specific changes
 	#
 	if tc-is-cross-compiler ; then
 		epatch "${FILESDIR}"/python-2.7.10-cross-h2py.patch
 		epatch "${FILESDIR}"/python-2.7.10-cross-hack-compiler.patch
 		sed -i 's:^python$EXE:${HOSTPYTHON}:' Lib/*/regen || die
 	fi
 	epatch "${FILESDIR}"/python-2.7.10-cross-setup-sysroot.patch
 	epatch "${FILESDIR}"/python-2.7.10-cross-distutils.patch
 	epatch "${FILESDIR}"/python-2.7.10-cross-sysconfig.patch
 	epatch "${FILESDIR}"/python-2.7.10-ldshared.patch
 	# Undo the @libdir@ change for portage's pym folder as it is always
 	# installed into /usr/lib/ and not the abi libdir.
 	sed -i \
 		-e '/portage.*pym/s:@@GENTOO_LIBDIR@@:lib:g' \
 		Lib/site.py || die

 	sed -i -e "s:sys.exec_prefix]:sys.exec_prefix, '/usr/local']:g" \
 		Lib/site.py || die "sed failed to add /usr/local to prefixes"

 	# Enable stealthy profile application; with this, `sysconfig` won't
 	# report on any CFLAGS in EXTRA_CFLAGS
 	epatch "${FILESDIR}"/python-2.7-clear-extra-cflags.patch
 	#
 	# END: ChromiumOS specific changes
 	#

 	# Fix for cross-compiling.
 	epatch "${FILESDIR}/python-2.7.5-nonfatal-compileall.patch"
 	epatch "${FILESDIR}/python-2.7.9-ncurses-pkg-config.patch"
 	epatch "${FILESDIR}/python-2.7.10-cross-compile-warn-test.patch"
 	epatch "${FILESDIR}/python-2.7.10-system-libffi.patch"
 	epatch "${FILESDIR}/python-2.7.15-sigint-handler.patch"

 	epatch_user

 	sed -i -e "s:@@GENTOO_LIBDIR@@:$(get_libdir):g" \
 		Lib/distutils/command/install.py \
 		Lib/distutils/sysconfig.py \
 		Lib/site.py \
 		Lib/sysconfig.py \
 		Lib/test/test_site.py \
 		Makefile.pre.in \
 		Modules/Setup.dist \
 		Modules/getpath.c \
 		setup.py || die "sed failed to replace @@GENTOO_LIBDIR@@"

 	eautoreconf
 }

 # There's a sad story behind this. When we've built our `python` and
 # `libpython.so` objects, we'll go to build all of our Python modules. This is
 # done with LD_LIBRARY_PATH set to our workdir, and is generally
 # well-sandboxed. Sadly, the compiler is a wrapper written in Python and
 # invoked via #!/usr/bin/python2, so **the compiler invocations will link to
 # the new, not-yet-installed libpython.so**.
 #
 # Usually, this isn't much of a problem. However, when we're building Python
 # with instrumentation enabled, libpython.so is where some of the key
 # instrumentation functions end up. Since everything links to libpython.so, and
 # since libpython.so shows up in link lines before libclang_rt.profile (where
 # these "key instrumentation functions" come from), the only binary we built
 # with USE=pgo_generate that has an actual definition for these functions is
 # libpython.so.
 #
 # Hence, the old python invoked by the wrapper looks for its profiling symbols
 # in the *new* libpython.so, doesn't find them, and gets sad.
 #
 # This can all be fixed by moving libclang_rt.profiles up before -lpython2.7 in
 # the commandline, which is easily doable. Doing so puts these profiling
 # symbols in every binary we produce, but only in pgo_generate builds. They're
 # all dynamic symbols, so keeping multiple definitions around should be OK.
 #
 # Clang is good about moving libclangrt_profile around, so we just parse its
 # output to determine where this static lib is located today.
 detect_libprofile_rt_location() {
 	local result
 	# Clang always gives quoted output. We're picking out the single arg
 	# with libclang_rt.profile from it, and discarding the quotes.
 	result=$(echo | \
 			$(tc-getCC) -### -fprofile-generate -x c - |& \
 			grep -oE '"[^"]+libclang_rt.profile[^"]+"' | \
 			tr -d '"')
 	[[ -n "${result}" ]] || die "libclangrt detection failed"
 	echo "${result}"
 }

 src_configure() {
 		# dbm module can be linked against berkdb or gdbm.
 		# Defaults to gdbm when both are enabled, #204343.
 		local disable
 		use berkdb   || use gdbm || disable+=" dbm"
 		use berkdb   || disable+=" _bsddb"
 		# disable automagic bluetooth headers detection
 		use bluetooth || export ac_cv_header_bluetooth_bluetooth_h=no
 		use gdbm     || disable+=" gdbm"
 		use ncurses  || disable+=" _curses _curses_panel"
 		use readline || disable+=" readline"
 		use sqlite   || disable+=" _sqlite3"
 		use ssl      || export PYTHON_DISABLE_SSL="1"
 		use tk       || disable+=" _tkinter"
 		use xml      || disable+=" _elementtree pyexpat" # _elementtree uses pyexpat.
 		export PYTHON_DISABLE_MODULES="${disable}"

 		if ! use xml; then
 			ewarn "You have configured Python without XML support."
 			ewarn "This is NOT a recommended configuration as you"
 			ewarn "may face problems parsing any XML documents."
 		fi

 	if [[ -n "${PYTHON_DISABLE_MODULES}" ]]; then
 		einfo "Disabled modules: ${PYTHON_DISABLE_MODULES}"
 	fi

 	if [[ "$(gcc-major-version)" -ge 4 ]]; then
 		append-flags -fwrapv
 	fi

 	filter-flags -malign-double

 	# https://bugs.gentoo.org/show_bug.cgi?id=50309
 	if is-flagq -O3; then
 		is-flagq -fstack-protector-all && replace-flags -O3 -O2
 		use hardened && replace-flags -O3 -O2
 	fi

 	# python2 build is running cross-compiled x86_64 binaries on build
 	# machine that may not have same ISA. Filter architecture specific
 	# flags as a workaround, https://crbug.com/1091706 .
 	if use amd64 && tc-is-cross-compiler; then
 		filter-flags '-march=*'
 	fi

 	if tc-is-cross-compiler; then
 		# Force some tests that try to poke fs paths.
 		export ac_cv_file__dev_ptc=no
 		export ac_cv_file__dev_ptmx=yes
 	fi

 	# Export CXX so it ends up in /usr/lib/python2.X/config/Makefile.
 	tc-export CXX
 	# The configure script fails to use pkg-config correctly.
 	# http://bugs.python.org/issue15506
 	export ac_cv_path_PKG_CONFIG=$(tc-getPKG_CONFIG)

 	# Set LDFLAGS so we link modules with -lpython2.7 correctly.
 	# Needed on FreeBSD unless Python 2.7 is already installed.
 	# Please query BSD team before removing this!
 	append-ldflags "-L."

 	tc-export CC
 	if use pgo_generate; then
 		tc-is-clang || die "Instrumentation is only supported when using clang"
 		# tc_extra_flags is an invention used to make cflags apply
 		# equally to Python's C modules and Python itself. This also
 		# prevents duplication between CFLAGS and LDFLAGS, which is a
 		# build error with -mllvm -options.
 		#
 		# This is a functional change in Python that breaks subversion
 		# (SWIG Python bindings rely on distutils.sysconfigs' ${CC}),
 		# so you should consider re-emerge'ing before trying to emerge
 		# anything else.
 		#
 		# We explicitly use /tmp here because this path is *baked into
 		# Python* as the place where profiles should go when Python is
 		# run. Hence, it has to be a well-known place that lives after
 		# `emerge`.
 		CC+=" -fprofile-generate=/tmp/python_profiles"

 		# LLVM intentionally low-balls vp-counters-per-site to save some
 		# binary size. If left to its default of 1, we get a diagnostic
 		# asking for it to be raised. Instead of tweaking it and having
 		# the issue silently appear again in the future, force dynamic
 		# allocation of counters. It's marginally slower, but less
 		# error-prone.
 		CC+=" -mllvm -vp-static-alloc=false"

 		append-ldflags "$(detect_libprofile_rt_location)"
 	fi

 	local dbmliborder
 	if use gdbm; then
 		dbmliborder+="${dbmliborder:+:}gdbm"
 	fi
 	if use berkdb; then
 		dbmliborder+="${dbmliborder:+:}bdb"
 	fi

 	BUILD_DIR="${WORKDIR}/${CHOST}"
 	mkdir -p "${BUILD_DIR}" || die
 	cd "${BUILD_DIR}" || die

 	ECONF_SOURCE="${S}" OPT="" \
 	econf \
 		--with-fpectl \
 		--enable-shared \
 		$(use_enable ipv6) \
 		$(use_with threads) \
 		$(use wide-unicode && echo "--enable-unicode=ucs4" || echo "--enable-unicode=ucs2") \
 		--infodir='${prefix}/share/info' \
 		--mandir='${prefix}/share/man' \
 		--with-computed-gotos \
 		--with-dbmliborder="${dbmliborder}" \
 		--with-libc="" \
 		--enable-loadable-sqlite-extensions \
 		--with-system-expat \
 		--with-system-ffi \
 		--without-ensurepip

 	if use threads && grep -q "#define POSIX_SEMAPHORES_NOT_ENABLED 1" pyconfig.h; then
 		eerror "configure has detected that the sem_open function is broken."
 		eerror "Please ensure that /dev/shm is mounted as a tmpfs with mode 1777."
 		die "Broken sem_open function (bug 496328)"
 	fi
 }

 src_compile() {
 	# Avoid invoking pgen for cross-compiles.
 	touch Include/graminit.h Python/graminit.c

 	# CFLAGS specified in configure get baked into the `sysconfig` module,
 	# which is consulted when building e.g. SWIG bindings for subversion.
 	# OPT, which we wiped out during configuration time anyway, allows us
 	# to pass flags that `sysconfig` doesn't see.
 	local extra_cflags=()
 	if use pgo_use && tc-is-clang; then
 		# If you're upgrading Python, please also run
 		# ./files/python2_gen_pgo.sh to build a new PGO profile.
 		if [[ "${PV}" != "${PROF_VERSION}" ]]; then
 			die "Please generate a new profile. Details in comments."
 		fi

 		extra_cflags=(
 			"-fprofile-use=${WORKDIR}/python-${PROF_VERSION}-pgo-prof.profdata"
 			"-Wno-backend-plugin"
 		)

 		# LTO only buys us ~2%, it increases binary size around 750KB,
 		# and it's entirely broken on aarch64 (LTO prompts clang to use
 		# its built-in assembler, which has issues with inline assembly
 		# in Python, apparently.)
 	fi

 	cd "${BUILD_DIR}" || die
 	EXTRA_CFLAGS="${extra_cflags[*]}" emake

 	# Work around bug 329499. See also bug 413751 and 457194.
 	if has_version dev-libs/libffi[pax_kernel]; then
 		pax-mark E python
 	else
 		pax-mark m python
 	fi
 }

 src_test() {
 	# Tests will not work when cross compiling.
 	if tc-is-cross-compiler; then
 		elog "Disabling tests due to crosscompiling."
 		return
 	fi

 	cd "${BUILD_DIR}" || die

 	# Skip failing tests.
 	local skipped_tests="distutils gdb"

 	for test in ${skipped_tests}; do
 		mv "${S}"/Lib/test/test_${test}.py "${T}"
 	done

 	# Daylight saving time problem
 	# https://bugs.python.org/issue22067
 	# https://bugs.gentoo.org/610628
 	local -x TZ=UTC

 	# Rerun failed tests in verbose mode (regrtest -w).
 	emake test EXTRATESTOPTS="-w" < /dev/tty
 	local result="$?"

 	for test in ${skipped_tests}; do
 		mv "${T}/test_${test}.py" "${S}"/Lib/test
 	done

 	elog "The following tests have been skipped:"
 	for test in ${skipped_tests}; do
 		elog "test_${test}.py"
 	done

 	elog "If you would like to run them, you may:"
 	elog "cd '${EPREFIX}/usr/$(get_libdir)/python${SLOT}/test'"
 	elog "and run the tests separately."

 	python_disable_pyc

 	if [[ "${result}" -ne 0 ]]; then
 		die "emake test failed"
 	fi
 }

 src_install() {
 	local libdir=${ED}/usr/$(get_libdir)/python${SLOT}

 	cd "${BUILD_DIR}" || die
 	emake DESTDIR="${D}" altinstall

 	sed -e "s/\(LDFLAGS=\).*/\1/" -i "${libdir}/config/Makefile" || die "sed failed"

 	# Fix collisions between different slots of Python.
 	mv "${ED}usr/bin/2to3" "${ED}usr/bin/2to3-${SLOT}"
 	mv "${ED}usr/bin/pydoc" "${ED}usr/bin/pydoc${SLOT}"
 	mv "${ED}usr/bin/idle" "${ED}usr/bin/idle${SLOT}"
 	rm -f "${ED}usr/bin/smtpd.py"

 	use berkdb || rm -r "${libdir}/"{bsddb,dbhash.py*,test/test_bsddb*} || die
 	use sqlite || rm -r "${libdir}/"{sqlite3,test/test_sqlite*} || die
 	use tk || rm -r "${ED}usr/bin/idle${SLOT}" "${libdir}/"{idlelib,lib-tk} || die
 	use elibc_uclibc && rm -fr "${libdir}/"{bsddb/test,test}

 	use threads || rm -r "${libdir}/multiprocessing" || die
 	use wininst || rm -r "${libdir}/distutils/command/"wininst-*.exe || die

 	dodoc "${S}"/Misc/{ACKS,HISTORY,NEWS}

 	if use examples; then
 		insinto /usr/share/doc/${PF}/examples
 		doins -r "${S}"/Tools
 	fi
 	insinto /usr/share/gdb/auto-load/usr/$(get_libdir) #443510
 	local libname=$(printf 'e:\n\t@echo $(INSTSONAME)\ninclude Makefile\n' | \
 		emake --no-print-directory -s -f - 2>/dev/null)
 	newins "${S}"/Tools/gdb/libpython.py "${libname}"-gdb.py

 	newconfd "${FILESDIR}/pydoc.conf" pydoc-${SLOT}
 	newinitd "${FILESDIR}/pydoc.init" pydoc-${SLOT}
 	sed \
 		-e "s:@PYDOC_PORT_VARIABLE@:PYDOC${SLOT/./_}_PORT:" \
 		-e "s:@PYDOC@:pydoc${SLOT}:" \
 		-i "${ED}etc/conf.d/pydoc-${SLOT}" "${ED}etc/init.d/pydoc-${SLOT}" || die "sed failed"

 	# for python-exec
 	local vars=( EPYTHON PYTHON_SITEDIR PYTHON_SCRIPTDIR )

 	# if not using a cross-compiler, use the fresh binary
 	if ! tc-is-cross-compiler; then
 		local -x PYTHON=./python
 		local -x LD_LIBRARY_PATH=${LD_LIBRARY_PATH+${LD_LIBRARY_PATH}:}${PWD}
 	else
 		vars=( PYTHON "${vars[@]}" )
 	fi

 	python_export "python${SLOT}" "${vars[@]}"
 	echo "EPYTHON='${EPYTHON}'" > epython.py || die
 	python_domodule epython.py

 	# python-exec wrapping support
 	local pymajor=${SLOT%.*}
 	mkdir -p "${D}${PYTHON_SCRIPTDIR}" || die
 	# python and pythonX
 	ln -s "../../../bin/python${SLOT}" "${D}${PYTHON_SCRIPTDIR}/python${pymajor}" || die
 	ln -s "python${pymajor}" "${D}${PYTHON_SCRIPTDIR}/python" || die
 	# python-config and pythonX-config
 	ln -s "../../../bin/python${SLOT}-config" "${D}${PYTHON_SCRIPTDIR}/python${pymajor}-config" || die
 	ln -s "python${pymajor}-config" "${D}${PYTHON_SCRIPTDIR}/python-config" || die
 	# 2to3, pydoc, pyvenv
 	ln -s "../../../bin/2to3-${SLOT}" "${D}${PYTHON_SCRIPTDIR}/2to3" || die
 	ln -s "../../../bin/pydoc${SLOT}" "${D}${PYTHON_SCRIPTDIR}/pydoc" || die
 	# idle
 	if use tk; then
 		ln -s "../../../bin/idle${SLOT}" "${D}${PYTHON_SCRIPTDIR}/idle" || die
 	fi

 	# The sysconfig module will actually read the pyconfig.h at runtime to see what kind
 	# of functionality is enabled in the build.  Deploy it behind the back of portage as
 	# need be.
 	ln "${ED}/usr/include/python${SLOT}/pyconfig.h" "${libdir}/pyconfig_h" || die

 	# Workaround https://bugs.gentoo.org/380569
 	keepdir /etc/env.d/python
 }

 eselect_python_update() {
 	if [[ -z "$(eselect python show)" || ! -f "${EROOT}usr/bin/$(eselect python show)" ]]; then
 		eselect python update
 	fi

 	if [[ -z "$(eselect python show --python${PV%%.*})" || ! -f "${EROOT}usr/bin/$(eselect python show --python${PV%%.*})" ]]; then
 		eselect python update --python${PV%%.*}
 	fi
 }

 pkg_postinst() {
 	eselect_python_update

 	local pyconfig="${EROOT}/usr/$(get_libdir)/python${SLOT}/pyconfig_h"
 	if [[ ! -e ${EROOT}/usr/include/python${SLOT}/pyconfig.h ]] ; then
 		# See pkg_preinst above for details.
 		install -D -m644 "${pyconfig}" "${EROOT}/usr/include/python${SLOT}/pyconfig.h" || die
 	fi
 	rm "${pyconfig}" || die
 }

 pkg_postrm() {
 	eselect_python_update
 }
	# Copyright 1999-2018 Gentoo Authors
	# Distributed under the terms of the GNU General Public License v2
	# $Header: /var/cvsroot/gentoo-x86/dev-lang/python/python-2.7.10.ebuild,v 1.2 2015/06/29 17:26:27 floppym Exp $

	EAPI="5"
	WANT_LIBTOOL="none"

	inherit autotools eutils flag-o-matic multilib pax-utils python-utils-r1 toolchain-funcs multiprocessing

	MY_P="Python-${PV}"
	PATCHSET_VERSION="2.7.15"

	DESCRIPTION="An interpreted, interactive, object-oriented programming language"
	HOMEPAGE="https://www.python.org/"

	# The version of Python our PGO profile was generated with. Using ${PV} makes
	# updates difficult, and we have tricks below to catch a mismatched profile
	# version.
	PROF_VERSION="2.7.15"

	SRC_URI="https://www.python.org/ftp/python/${PV}/${MY_P}.tar.xz
	https://dev.gentoo.org/~floppym/python/python-gentoo-patches-${PATCHSET_VERSION}.tar.xz
	pgo_use? ( gs://chromeos-localmirror/distfiles/python-${PROF_VERSION}-pgo-prof.profdata.tar.xz )"

	LICENSE="PSF-2"
	SLOT="2.7"
	KEYWORDS="*"
	IUSE="-berkdb bluetooth build doc elibc_uclibc examples gdbm hardened ipv6 pgo_generate +pgo_use libressl +ncurses +readline sqlite +ssl +threads tk +wide-unicode wininst +xml"

	REQUIRED_USE="pgo_generate? ( !pgo_use )"

	# Workaround: re-emerging this after emerging a `pgo_generate` Python gives us
	# a really bad time, since we'll try to write to profiles in "restricted"
	# places somehow. Specifying this profile file has LLVM write profiles to
	# /dev/null, which is always available.
	export LLVM_PROFILE_FILE="/dev/null"

	# Do not add a dependency on dev-lang/python to this ebuild.
	# If you need to apply a patch which requires python for bootstrapping, please
	# run the bootstrap code on your dev box and include the results in the
	# patchset. See bug 447752.

	RDEPEND="app-arch/bzip2:0=
	>=sys-libs/zlib-1.1.3:0=
	virtual/libffi:=
	virtual/libintl
	berkdb? ( \|\| (
	sys-libs/db:5.3
	sys-libs/db:5.1
	sys-libs/db:4.8
	sys-libs/db:4.7
	sys-libs/db:4.6
	sys-libs/db:4.5
	sys-libs/db:4.4
	sys-libs/db:4.3
	sys-libs/db:4.2
	) )
	gdbm? ( sys-libs/gdbm:0=[berkdb] )
	ncurses? ( >=sys-libs/ncurses-5.2:0= )
	readline? ( >=sys-libs/readline-4.1:0= )
	sqlite? ( >=dev-db/sqlite-3.3.8:3= )
	ssl? (
	!libressl? ( dev-libs/openssl:0= )
	libressl? ( dev-libs/libressl:0= )
	)
	tk? (
	>=dev-lang/tcl-8.0:0=
	>=dev-lang/tk-8.0:0=
	dev-tcltk/blt:0=
	dev-tcltk/tix
	)
	xml? ( >=dev-libs/expat-2.1 )
	!!<sys-apps/portage-2.1.9"
	# bluetooth requires headers from bluez
	DEPEND="${RDEPEND}
	bluetooth? ( net-wireless/bluez )
	virtual/pkgconfig
	>=sys-devel/autoconf-2.65
	!sys-devel/gcc[libffi(-)]"
	RDEPEND+=" !build? ( app-misc/mime-types )
	doc? ( dev-python/python-docs:${SLOT} )"
	PDEPEND=">=app-eselect/eselect-python-20140125-r1"

	S="${WORKDIR}/${MY_P}"

	pkg_setup() {
	if use berkdb; then
	ewarn "'bsddb' module is out-of-date and no longer maintained inside"
	ewarn "dev-lang/python. 'bsddb' and 'dbhash' modules have been additionally"
	ewarn "removed in Python 3. A maintained alternative of 'bsddb3' module"
	ewarn "is provided by dev-python/bsddb3."
	else
	if has_version "=${CATEGORY}/${PN}-${PV%%.}[berkdb]"; then
	ewarn "You are migrating from =${CATEGORY}/${PN}-${PV%%.}[berkdb]"
	ewarn "to =${CATEGORY}/${PN}-${PV%%.}[-berkdb]."
	ewarn "You might need to migrate your databases."
	fi
	fi
	}

	src_prepare() {
	# According to the comments at the top of cgi.py, Linux vendors need to
	# patch the shebang in cgi.py. We'll ignore the comment about not using
	# "/usr/bin/env python" and use it anyway.
	sed -i -e '1 s:^#!.*$:#! /usr/bin/env python:' Lib/cgi.py \|\| die

	# Ensure that internal copies of expat, libffi and zlib are not used.
	rm -r Modules/expat \|\| die
	rm -r Modules/_ctypes/libffi* \|\| die
	rm -r Modules/zlib \|\| die

	if tc-is-cross-compiler; then
	local EPATCH_EXCLUDE="*-Regenerate-platform-specific-modules.patch"
	fi

	EPATCH_SUFFIX="patch" EPATCH_FORCE="yes" epatch "${WORKDIR}/patches"

	#
	# START: ChromiumOS specific changes
	#
	if tc-is-cross-compiler ; then
	epatch "${FILESDIR}"/python-2.7.10-cross-h2py.patch
	epatch "${FILESDIR}"/python-2.7.10-cross-hack-compiler.patch
	sed -i 's:^python$EXE:${HOSTPYTHON}:' Lib/*/regen \|\| die
	fi
	epatch "${FILESDIR}"/python-2.7.10-cross-setup-sysroot.patch
	epatch "${FILESDIR}"/python-2.7.10-cross-distutils.patch
	epatch "${FILESDIR}"/python-2.7.10-cross-sysconfig.patch
	epatch "${FILESDIR}"/python-2.7.10-ldshared.patch
	# Undo the @libdir@ change for portage's pym folder as it is always
	# installed into /usr/lib/ and not the abi libdir.
	sed -i \
	-e '/portage.*pym/s:@@GENTOO_LIBDIR@@:lib:g' \
	Lib/site.py \|\| die

	sed -i -e "s:sys.exec_prefix]:sys.exec_prefix, '/usr/local']:g" \
	Lib/site.py \|\| die "sed failed to add /usr/local to prefixes"

	# Enable stealthy profile application; with this, `sysconfig` won't
	# report on any CFLAGS in EXTRA_CFLAGS
	epatch "${FILESDIR}"/python-2.7-clear-extra-cflags.patch
	#
	# END: ChromiumOS specific changes
	#

	# Fix for cross-compiling.
	epatch "${FILESDIR}/python-2.7.5-nonfatal-compileall.patch"
	epatch "${FILESDIR}/python-2.7.9-ncurses-pkg-config.patch"
	epatch "${FILESDIR}/python-2.7.10-cross-compile-warn-test.patch"
	epatch "${FILESDIR}/python-2.7.10-system-libffi.patch"
	epatch "${FILESDIR}/python-2.7.15-sigint-handler.patch"

	epatch_user

	sed -i -e "s:@@GENTOO_LIBDIR@@:$(get_libdir):g" \
	Lib/distutils/command/install.py \
	Lib/distutils/sysconfig.py \
	Lib/site.py \
	Lib/sysconfig.py \
	Lib/test/test_site.py \
	Makefile.pre.in \
	Modules/Setup.dist \
	Modules/getpath.c \
	setup.py \|\| die "sed failed to replace @@GENTOO_LIBDIR@@"

	eautoreconf
	}

	# There's a sad story behind this. When we've built our `python` and
	# `libpython.so` objects, we'll go to build all of our Python modules. This is
	# done with LD_LIBRARY_PATH set to our workdir, and is generally
	# well-sandboxed. Sadly, the compiler is a wrapper written in Python and
	# invoked via #!/usr/bin/python2, so **the compiler invocations will link to
	# the new, not-yet-installed libpython.so**.
	#
	# Usually, this isn't much of a problem. However, when we're building Python
	# with instrumentation enabled, libpython.so is where some of the key
	# instrumentation functions end up. Since everything links to libpython.so, and
	# since libpython.so shows up in link lines before libclang_rt.profile (where
	# these "key instrumentation functions" come from), the only binary we built
	# with USE=pgo_generate that has an actual definition for these functions is
	# libpython.so.
	#
	# Hence, the old python invoked by the wrapper looks for its profiling symbols
	# in the new libpython.so, doesn't find them, and gets sad.
	#
	# This can all be fixed by moving libclang_rt.profiles up before -lpython2.7 in
	# the commandline, which is easily doable. Doing so puts these profiling
	# symbols in every binary we produce, but only in pgo_generate builds. They're
	# all dynamic symbols, so keeping multiple definitions around should be OK.
	#
	# Clang is good about moving libclangrt_profile around, so we just parse its
	# output to determine where this static lib is located today.
	detect_libprofile_rt_location() {
	local result
	# Clang always gives quoted output. We're picking out the single arg
	# with libclang_rt.profile from it, and discarding the quotes.
	result=$(echo \| \
	$(tc-getCC) -### -fprofile-generate -x c - \|& \
	grep -oE '"[^"]+libclang_rt.profile[^"]+"' \| \
	tr -d '"')
	[[ -n "${result}" ]] \|\| die "libclangrt detection failed"
	echo "${result}"
	}

	src_configure() {
	# dbm module can be linked against berkdb or gdbm.
	# Defaults to gdbm when both are enabled, #204343.
	local disable
	use berkdb \|\| use gdbm \|\| disable+=" dbm"
	use berkdb \|\| disable+=" _bsddb"
	# disable automagic bluetooth headers detection
	use bluetooth \|\| export ac_cv_header_bluetooth_bluetooth_h=no
	use gdbm \|\| disable+=" gdbm"
	use ncurses \|\| disable+=" _curses _curses_panel"
	use readline \|\| disable+=" readline"
	use sqlite \|\| disable+=" _sqlite3"
	use ssl \|\| export PYTHON_DISABLE_SSL="1"
	use tk \|\| disable+=" _tkinter"
	use xml \|\| disable+=" _elementtree pyexpat" # _elementtree uses pyexpat.
	export PYTHON_DISABLE_MODULES="${disable}"

	if ! use xml; then
	ewarn "You have configured Python without XML support."
	ewarn "This is NOT a recommended configuration as you"
	ewarn "may face problems parsing any XML documents."
	fi

	if [[ -n "${PYTHON_DISABLE_MODULES}" ]]; then
	einfo "Disabled modules: ${PYTHON_DISABLE_MODULES}"
	fi

	if [[ "$(gcc-major-version)" -ge 4 ]]; then
	append-flags -fwrapv
	fi

	filter-flags -malign-double

	# https://bugs.gentoo.org/show_bug.cgi?id=50309
	if is-flagq -O3; then
	is-flagq -fstack-protector-all && replace-flags -O3 -O2
	use hardened && replace-flags -O3 -O2
	fi

	# python2 build is running cross-compiled x86_64 binaries on build
	# machine that may not have same ISA. Filter architecture specific
	# flags as a workaround, https://crbug.com/1091706 .
	if use amd64 && tc-is-cross-compiler; then
	filter-flags '-march=*'
	fi

	if tc-is-cross-compiler; then
	# Force some tests that try to poke fs paths.
	export ac_cv_file__dev_ptc=no
	export ac_cv_file__dev_ptmx=yes
	fi

	# Export CXX so it ends up in /usr/lib/python2.X/config/Makefile.
	tc-export CXX
	# The configure script fails to use pkg-config correctly.
	# http://bugs.python.org/issue15506
	export ac_cv_path_PKG_CONFIG=$(tc-getPKG_CONFIG)

	# Set LDFLAGS so we link modules with -lpython2.7 correctly.
	# Needed on FreeBSD unless Python 2.7 is already installed.
	# Please query BSD team before removing this!
	append-ldflags "-L."

	tc-export CC
	if use pgo_generate; then
	tc-is-clang \|\| die "Instrumentation is only supported when using clang"
	# tc_extra_flags is an invention used to make cflags apply
	# equally to Python's C modules and Python itself. This also
	# prevents duplication between CFLAGS and LDFLAGS, which is a
	# build error with -mllvm -options.
	#
	# This is a functional change in Python that breaks subversion
	# (SWIG Python bindings rely on distutils.sysconfigs' ${CC}),
	# so you should consider re-emerge'ing before trying to emerge
	# anything else.
	#
	# We explicitly use /tmp here because this path is *baked into
	# Python* as the place where profiles should go when Python is
	# run. Hence, it has to be a well-known place that lives after
	# `emerge`.
	CC+=" -fprofile-generate=/tmp/python_profiles"

	# LLVM intentionally low-balls vp-counters-per-site to save some
	# binary size. If left to its default of 1, we get a diagnostic
	# asking for it to be raised. Instead of tweaking it and having
	# the issue silently appear again in the future, force dynamic
	# allocation of counters. It's marginally slower, but less
	# error-prone.
	CC+=" -mllvm -vp-static-alloc=false"

	append-ldflags "$(detect_libprofile_rt_location)"
	fi

	local dbmliborder
	if use gdbm; then
	dbmliborder+="${dbmliborder:+:}gdbm"
	fi
	if use berkdb; then
	dbmliborder+="${dbmliborder:+:}bdb"
	fi

	BUILD_DIR="${WORKDIR}/${CHOST}"
	mkdir -p "${BUILD_DIR}" \|\| die
	cd "${BUILD_DIR}" \|\| die

	ECONF_SOURCE="${S}" OPT="" \
	econf \
	--with-fpectl \
	--enable-shared \
	$(use_enable ipv6) \
	$(use_with threads) \
	$(use wide-unicode && echo "--enable-unicode=ucs4" \|\| echo "--enable-unicode=ucs2") \
	--infodir='${prefix}/share/info' \
	--mandir='${prefix}/share/man' \
	--with-computed-gotos \
	--with-dbmliborder="${dbmliborder}" \
	--with-libc="" \
	--enable-loadable-sqlite-extensions \
	--with-system-expat \
	--with-system-ffi \
	--without-ensurepip

	if use threads && grep -q "#define POSIX_SEMAPHORES_NOT_ENABLED 1" pyconfig.h; then
	eerror "configure has detected that the sem_open function is broken."
	eerror "Please ensure that /dev/shm is mounted as a tmpfs with mode 1777."
	die "Broken sem_open function (bug 496328)"
	fi
	}

	src_compile() {
	# Avoid invoking pgen for cross-compiles.
	touch Include/graminit.h Python/graminit.c

	# CFLAGS specified in configure get baked into the `sysconfig` module,
	# which is consulted when building e.g. SWIG bindings for subversion.
	# OPT, which we wiped out during configuration time anyway, allows us
	# to pass flags that `sysconfig` doesn't see.
	local extra_cflags=()
	if use pgo_use && tc-is-clang; then
	# If you're upgrading Python, please also run
	# ./files/python2_gen_pgo.sh to build a new PGO profile.
	if [[ "${PV}" != "${PROF_VERSION}" ]]; then
	die "Please generate a new profile. Details in comments."
	fi

	extra_cflags=(
	"-fprofile-use=${WORKDIR}/python-${PROF_VERSION}-pgo-prof.profdata"
	"-Wno-backend-plugin"
	)

	# LTO only buys us ~2%, it increases binary size around 750KB,
	# and it's entirely broken on aarch64 (LTO prompts clang to use
	# its built-in assembler, which has issues with inline assembly
	# in Python, apparently.)
	fi

	cd "${BUILD_DIR}" \|\| die
	EXTRA_CFLAGS="${extra_cflags[*]}" emake

	# Work around bug 329499. See also bug 413751 and 457194.
	if has_version dev-libs/libffi[pax_kernel]; then
	pax-mark E python
	else
	pax-mark m python
	fi
	}

	src_test() {
	# Tests will not work when cross compiling.
	if tc-is-cross-compiler; then
	elog "Disabling tests due to crosscompiling."
	return
	fi

	cd "${BUILD_DIR}" \|\| die

	# Skip failing tests.
	local skipped_tests="distutils gdb"

	for test in ${skipped_tests}; do
	mv "${S}"/Lib/test/test_${test}.py "${T}"
	done

	# Daylight saving time problem
	# https://bugs.python.org/issue22067
	# https://bugs.gentoo.org/610628
	local -x TZ=UTC

	# Rerun failed tests in verbose mode (regrtest -w).
	emake test EXTRATESTOPTS="-w" < /dev/tty
	local result="$?"

	for test in ${skipped_tests}; do
	mv "${T}/test_${test}.py" "${S}"/Lib/test
	done

	elog "The following tests have been skipped:"
	for test in ${skipped_tests}; do
	elog "test_${test}.py"
	done

	elog "If you would like to run them, you may:"
	elog "cd '${EPREFIX}/usr/$(get_libdir)/python${SLOT}/test'"
	elog "and run the tests separately."

	python_disable_pyc

	if [[ "${result}" -ne 0 ]]; then
	die "emake test failed"
	fi
	}

	src_install() {
	local libdir=${ED}/usr/$(get_libdir)/python${SLOT}

	cd "${BUILD_DIR}" \|\| die
	emake DESTDIR="${D}" altinstall

	sed -e "s/\(LDFLAGS=\).*/\1/" -i "${libdir}/config/Makefile" \|\| die "sed failed"

	# Fix collisions between different slots of Python.
	mv "${ED}usr/bin/2to3" "${ED}usr/bin/2to3-${SLOT}"
	mv "${ED}usr/bin/pydoc" "${ED}usr/bin/pydoc${SLOT}"
	mv "${ED}usr/bin/idle" "${ED}usr/bin/idle${SLOT}"
	rm -f "${ED}usr/bin/smtpd.py"

	use berkdb \|\| rm -r "${libdir}/"{bsddb,dbhash.py,test/test_bsddb} \|\| die
	use sqlite \|\| rm -r "${libdir}/"{sqlite3,test/test_sqlite*} \|\| die
	use tk \|\| rm -r "${ED}usr/bin/idle${SLOT}" "${libdir}/"{idlelib,lib-tk} \|\| die
	use elibc_uclibc && rm -fr "${libdir}/"{bsddb/test,test}

	use threads \|\| rm -r "${libdir}/multiprocessing" \|\| die
	use wininst \|\| rm -r "${libdir}/distutils/command/"wininst-*.exe \|\| die

	dodoc "${S}"/Misc/{ACKS,HISTORY,NEWS}

	if use examples; then
	insinto /usr/share/doc/${PF}/examples
	doins -r "${S}"/Tools
	fi
	insinto /usr/share/gdb/auto-load/usr/$(get_libdir) #443510
	local libname=$(printf 'e:\n\t@echo $(INSTSONAME)\ninclude Makefile\n' \| \
	emake --no-print-directory -s -f - 2>/dev/null)
	newins "${S}"/Tools/gdb/libpython.py "${libname}"-gdb.py

	newconfd "${FILESDIR}/pydoc.conf" pydoc-${SLOT}
	newinitd "${FILESDIR}/pydoc.init" pydoc-${SLOT}
	sed \
	-e "s:@PYDOC_PORT_VARIABLE@:PYDOC${SLOT/./_}_PORT:" \
	-e "s:@PYDOC@:pydoc${SLOT}:" \
	-i "${ED}etc/conf.d/pydoc-${SLOT}" "${ED}etc/init.d/pydoc-${SLOT}" \|\| die "sed failed"

	# for python-exec
	local vars=( EPYTHON PYTHON_SITEDIR PYTHON_SCRIPTDIR )

	# if not using a cross-compiler, use the fresh binary
	if ! tc-is-cross-compiler; then
	local -x PYTHON=./python
	local -x LD_LIBRARY_PATH=${LD_LIBRARY_PATH+${LD_LIBRARY_PATH}:}${PWD}
	else
	vars=( PYTHON "${vars[@]}" )
	fi

	python_export "python${SLOT}" "${vars[@]}"
	echo "EPYTHON='${EPYTHON}'" > epython.py \|\| die
	python_domodule epython.py

	# python-exec wrapping support
	local pymajor=${SLOT%.*}
	mkdir -p "${D}${PYTHON_SCRIPTDIR}" \|\| die
	# python and pythonX
	ln -s "../../../bin/python${SLOT}" "${D}${PYTHON_SCRIPTDIR}/python${pymajor}" \|\| die
	ln -s "python${pymajor}" "${D}${PYTHON_SCRIPTDIR}/python" \|\| die
	# python-config and pythonX-config
	ln -s "../../../bin/python${SLOT}-config" "${D}${PYTHON_SCRIPTDIR}/python${pymajor}-config" \|\| die
	ln -s "python${pymajor}-config" "${D}${PYTHON_SCRIPTDIR}/python-config" \|\| die
	# 2to3, pydoc, pyvenv
	ln -s "../../../bin/2to3-${SLOT}" "${D}${PYTHON_SCRIPTDIR}/2to3" \|\| die
	ln -s "../../../bin/pydoc${SLOT}" "${D}${PYTHON_SCRIPTDIR}/pydoc" \|\| die
	# idle
	if use tk; then
	ln -s "../../../bin/idle${SLOT}" "${D}${PYTHON_SCRIPTDIR}/idle" \|\| die
	fi

	# The sysconfig module will actually read the pyconfig.h at runtime to see what kind
	# of functionality is enabled in the build. Deploy it behind the back of portage as
	# need be.
	ln "${ED}/usr/include/python${SLOT}/pyconfig.h" "${libdir}/pyconfig_h" \|\| die

	# Workaround https://bugs.gentoo.org/380569
	keepdir /etc/env.d/python
	}

	eselect_python_update() {
	if [[ -z "$(eselect python show)" \|\| ! -f "${EROOT}usr/bin/$(eselect python show)" ]]; then
	eselect python update
	fi

	if [[ -z "$(eselect python show --python${PV%%.})" \|\| ! -f "${EROOT}usr/bin/$(eselect python show --python${PV%%.})" ]]; then
	eselect python update --python${PV%%.*}
	fi
	}

	pkg_postinst() {
	eselect_python_update

	local pyconfig="${EROOT}/usr/$(get_libdir)/python${SLOT}/pyconfig_h"
	if [[ ! -e ${EROOT}/usr/include/python${SLOT}/pyconfig.h ]] ; then
	# See pkg_preinst above for details.
	install -D -m644 "${pyconfig}" "${EROOT}/usr/include/python${SLOT}/pyconfig.h" \|\| die
	fi
	rm "${pyconfig}" \|\| die
	}

	pkg_postrm() {
	eselect_python_update
	}