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      1 # multiarch.m4 serial 5
      2 dnl Copyright (C) 2008, 2009 Free Software Foundation, Inc.
      3 dnl This file is free software; the Free Software Foundation
      4 dnl gives unlimited permission to copy and/or distribute it,
      5 dnl 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 
     22 AC_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