1# multiarch.m4 serial 7
2dnl Copyright (C) 2008-2012 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 Mac OS 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 APPLE_UNIVERSAL_BUILD accordingly.
20
21AC_DEFUN_ONCE([gl_MULTIARCH],
22[
23  dnl Code similar to autoconf-2.63 AC_C_BIGENDIAN.
24  gl_cv_c_multiarch=no
25  AC_COMPILE_IFELSE(
26    [AC_LANG_SOURCE(
27      [[#ifndef __APPLE_CC__
28         not a universal capable compiler
29        #endif
30        typedef int dummy;
31      ]])],
32    [
33     dnl Check for potential -arch flags.  It is not universal unless
34     dnl there are at least two -arch flags with different values.
35     arch=
36     prev=
37     for word in ${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}; do
38       if test -n "$prev"; then
39         case $word in
40           i?86 | x86_64 | ppc | ppc64)
41             if test -z "$arch" || test "$arch" = "$word"; then
42               arch="$word"
43             else
44               gl_cv_c_multiarch=yes
45             fi
46             ;;
47         esac
48         prev=
49       else
50         if test "x$word" = "x-arch"; then
51           prev=arch
52         fi
53       fi
54     done
55    ])
56  if test $gl_cv_c_multiarch = yes; then
57    APPLE_UNIVERSAL_BUILD=1
58  else
59    APPLE_UNIVERSAL_BUILD=0
60  fi
61  AC_SUBST([APPLE_UNIVERSAL_BUILD])
62])
63