1# multiarch.m4 serial 5
2dnl Copyright (C) 2008, 2009 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7# Determine whether the compiler is or may be producing universal binaries.
8#
9# On MacOS X 10.5 and later systems, the user can create libraries and
10# executables that work on multiple system types--known as "fat" or
11# "universal" binaries--by specifying multiple '-arch' options to the
12# compiler but only a single '-arch' option to the preprocessor.  Like
13# this:
14#
15#     ./configure CC="gcc -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
16#                 CXX="g++ -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
17#                 CPP="gcc -E" CXXCPP="g++ -E"
18#
19# Detect this situation and set the macro AA_APPLE_UNIVERSAL_BUILD at the
20# beginning of config.h and set APPLE_UNIVERSAL_BUILD accordingly.
21
22AC_DEFUN_ONCE([gl_MULTIARCH],
23[
24  dnl Code similar to autoconf-2.63 AC_C_BIGENDIAN.
25  gl_cv_c_multiarch=no
26  AC_COMPILE_IFELSE(
27    [AC_LANG_SOURCE(
28      [[#ifndef __APPLE_CC__
29         not a universal capable compiler
30        #endif
31        typedef int dummy;
32      ]])],
33    [
34     dnl Check for potential -arch flags.  It is not universal unless
35     dnl there are at least two -arch flags with different values.
36     arch=
37     prev=
38     for word in ${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}; do
39       if test -n "$prev"; then
40         case $word in
41           i?86 | x86_64 | ppc | ppc64)
42             if test -z "$arch" || test "$arch" = "$word"; then
43               arch="$word"
44             else
45               gl_cv_c_multiarch=yes
46             fi
47             ;;
48         esac
49         prev=
50       else
51         if test "x$word" = "x-arch"; then
52           prev=arch
53         fi
54       fi
55     done
56    ])
57  if test $gl_cv_c_multiarch = yes; then
58    AC_DEFINE([AA_APPLE_UNIVERSAL_BUILD], [1],
59      [Define if the compiler is building for multiple architectures of Apple platforms at once.])
60    APPLE_UNIVERSAL_BUILD=1
61  else
62    APPLE_UNIVERSAL_BUILD=0
63  fi
64  AC_SUBST([APPLE_UNIVERSAL_BUILD])
65])
66