Fix configure.ac variables to point to SYSROOT rather than the build host's root.

Without these changes, mod_wsgi will fail to compile as it will incorrectly
try to use the host's python binary and include directories.

crbug.com/345821
--- a/configure.ac
+++ b/configure.ac
@@ -41,8 +41,8 @@ AC_SUBST(APXS)
 
 AC_MSG_CHECKING(Apache version)
 HTTPD="`${APXS} -q SBINDIR`/`${APXS} -q TARGET`"
-HTTPD_INCLUDEDIR="`${APXS} -q INCLUDEDIR`"
-if test -x ${HTTPD}; then
+HTTPD_INCLUDEDIR="${SYSROOT}`${APXS} -q INCLUDEDIR`"
+if false; then
     HTTPD_VERSION=`${HTTPD} -v | awk '/version/ {print $3}' \
      | awk -F/ '{print $2}'`
 else
@@ -77,9 +77,9 @@ PYTHON_VERSION=`${PYTHON} -c 'from sys import stdout; \
     from distutils import sysconfig; \
     stdout.write((sysconfig.get_config_var("VERSION")))'`
 
-CPPFLAGS1=`${PYTHON} -c 'from sys import stdout; \
+CPPFLAGS1="-I${SYSROOT}"`${PYTHON} -c 'from sys import stdout; \
     from distutils import sysconfig; \
-    stdout.write("-I" + sysconfig.get_config_var("INCLUDEPY"))'`
+    stdout.write(sysconfig.get_config_var("INCLUDEPY"))'`
 
 CPPFLAGS2=`${PYTHON} -c 'from sys import stdout; \
     from distutils import sysconfig; \
@@ -96,7 +96,7 @@ CPPFLAGS="${CPPFLAGS} ${CPPFLAGS1} ${CPPFLAGS2} ${CPPFLAGS3}"
 
 AC_SUBST(CPPFLAGS)
 
-PYTHONLIBDIR=`${PYTHON} -c 'from sys import stdout; \
+PYTHONLIBDIR="${SYSROOT}"`${PYTHON} -c 'from sys import stdout; \
     from distutils import sysconfig; \
     stdout.write(sysconfig.get_config_var("LIBDIR"))'`
 PYTHONCFGDIR=`${PYTHON} -c 'from sys import stdout; \