mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-11-25 07:28:20 +00:00
642fd607b8
* m4/byteswap.m4: Copy from Gnulib. This fixes a configure glitch on macOS reported by Mattias Engdegård
42 lines
1.4 KiB
Plaintext
42 lines
1.4 KiB
Plaintext
# byteswap.m4
|
|
# serial 7
|
|
dnl Copyright (C) 2005, 2007, 2009-2024 Free Software Foundation, Inc.
|
|
dnl This file is free software; the Free Software Foundation
|
|
dnl gives unlimited permission to copy and/or distribute it,
|
|
dnl with or without modifications, as long as this notice is preserved.
|
|
|
|
dnl Written by Oskar Liljeblad.
|
|
|
|
AC_DEFUN([gl_BYTESWAP],
|
|
[
|
|
dnl Prerequisites of lib/byteswap.in.h.
|
|
AC_CHECK_HEADERS_ONCE([byteswap.h])
|
|
if test $ac_cv_header_byteswap_h = yes; then
|
|
AC_CACHE_CHECK([for working bswap_16, bswap_32, bswap_64],
|
|
[gl_cv_header_working_byteswap_h],
|
|
[gl_cv_header_working_byteswap_h=no
|
|
dnl Check that floating point arguments work.
|
|
dnl This also checks C libraries with implementations like
|
|
dnl '#define bswap_16(x) (((x) >> 8 & 0xff) | (((x) & 0xff) << 8))'
|
|
dnl that mistakenly evaluate their arguments multiple times.
|
|
AC_COMPILE_IFELSE(
|
|
[AC_LANG_PROGRAM(
|
|
[[#include <byteswap.h>
|
|
]],
|
|
[[int value_16 = bswap_16 (0.0);
|
|
int value_32 = bswap_32 (0.0);
|
|
int value_64 = bswap_64 (0.0);
|
|
return !(value_16 + value_32 + value_64);
|
|
]])
|
|
],
|
|
[gl_cv_header_working_byteswap_h=yes],
|
|
[gl_cv_header_working_byteswap_h=no])
|
|
])
|
|
fi
|
|
if test "$gl_cv_header_working_byteswap_h" = yes; then
|
|
GL_GENERATE_BYTESWAP_H=false
|
|
else
|
|
GL_GENERATE_BYTESWAP_H=true
|
|
fi
|
|
])
|