| https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=234fc6c86613ed3f366dd1d88996e4d5d85ee222 |
| |
| From 234fc6c86613ed3f366dd1d88996e4d5d85ee222 Mon Sep 17 00:00:00 2001 |
| From: Paul Eggert <eggert@cs.ucla.edu> |
| Date: Wed, 27 Jul 2022 08:53:35 -0700 |
| Subject: Port AC_C_BIGENDIAN to cross gcc -std=c11 -flto |
| |
| * lib/autoconf/c.m4 (AC_C_BIGENDIAN): Improve the |
| inherently-unportable grep trick well enough to survive gcc |
| -std=c11 -flto when cross-compiling (sr#110687). |
| --- a/lib/autoconf/c.m4 |
| +++ b/lib/autoconf/c.m4 |
| @@ -1838,8 +1838,8 @@ AC_DEFUN([AC_C_BIGENDIAN], |
| [ac_cv_c_bigendian=no], |
| [ac_cv_c_bigendian=yes], |
| [# Try to guess by grepping values from an object file. |
| - AC_COMPILE_IFELSE( |
| - [AC_LANG_PROGRAM( |
| + AC_LINK_IFELSE( |
| + [AC_LANG_SOURCE( |
| [[unsigned short int ascii_mm[] = |
| { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 }; |
| unsigned short int ascii_ii[] = |
| @@ -1854,13 +1854,20 @@ AC_DEFUN([AC_C_BIGENDIAN], |
| int use_ebcdic (int i) { |
| return ebcdic_mm[i] + ebcdic_ii[i]; |
| } |
| - extern int foo; |
| - ]], |
| - [[return use_ascii (foo) == use_ebcdic (foo);]])], |
| - [if grep BIGenDianSyS conftest.$ac_objext >/dev/null; then |
| + int |
| + main (int argc, char **argv) |
| + { |
| + /* Intimidate the compiler so that it does not |
| + optimize the arrays away. */ |
| + char *p = argv[0]; |
| + ascii_mm[1] = *p++; ebcdic_mm[1] = *p++; |
| + ascii_ii[1] = *p++; ebcdic_ii[1] = *p++; |
| + return use_ascii (argc) == use_ebcdic (*p); |
| + }]])], |
| + [if grep BIGenDianSyS conftest$ac_exeext >/dev/null; then |
| ac_cv_c_bigendian=yes |
| fi |
| - if grep LiTTleEnDian conftest.$ac_objext >/dev/null ; then |
| + if grep LiTTleEnDian conftest$ac_exeext >/dev/null ; then |
| if test "$ac_cv_c_bigendian" = unknown; then |
| ac_cv_c_bigendian=no |
| else |
| cgit v1.1 |
