1# multiarch.m4 serial 9
2dnl Copyright (C) 2008-2020 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  AC_CACHE_CHECK([whether the compiler produces multi-arch binaries],
25    [gl_cv_c_multiarch],
26    [gl_cv_c_multiarch=no
27     AC_COMPILE_IFELSE(
28       [AC_LANG_SOURCE(
29         [[#ifndef __APPLE_CC__
30            not a universal capable compiler
31           #endif
32           typedef int dummy;
33         ]])],
34       [
35        dnl Check for potential -arch flags.  It is not universal unless
36        dnl there are at least two -arch flags with different values.
37        arch=
38        prev=
39        for word in ${CC} ${CFLAGS} ${CPPFLAGS} ${LDFLAGS}; do
40          if test -n "$prev"; then
41            case $word in
42              i?86 | x86_64 | ppc | ppc64 | arm | arm64)
43                if test -z "$arch" || test "$arch" = "$word"; then
44                  arch="$word"
45                else
46                  gl_cv_c_multiarch=yes
47                fi
48                ;;
49            esac
50            prev=
51          else
52            if test "x$word" = "x-arch"; then
53              prev=arch
54            fi
55          fi
56        done
57       ])
58    ])
59  if test $gl_cv_c_multiarch = yes; then
60    APPLE_UNIVERSAL_BUILD=1
61  else
62    APPLE_UNIVERSAL_BUILD=0
63  fi
64  AC_SUBST([APPLE_UNIVERSAL_BUILD])
65])
66