m4/ld-version-script.m4

   1 # ld-version-script.m4 serial 3
   2 dnl Copyright (C) 2008-2014 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 dnl From Simon Josefsson
   8
   9 # FIXME: The test below returns a false positive for mingw
  10 # cross-compiles, 'local:' statements does not reduce number of
  11 # exported symbols in a DLL.  Use --disable-ld-version-script to work
  12 # around the problem.
  13
  14 # gl_LD_VERSION_SCRIPT
  15 # --------------------
  16 # Check if LD supports linker scripts, and define automake conditional
  17 # HAVE_LD_VERSION_SCRIPT if so.
  18 AC_DEFUN([gl_LD_VERSION_SCRIPT],
  19 [
  20   AC_ARG_ENABLE([ld-version-script],
  21     AS_HELP_STRING([--enable-ld-version-script],
  22       [enable linker version script (default is enabled when possible)]),
  23       [have_ld_version_script=$enableval], [])
  24   if test -z "$have_ld_version_script"; then
  25     AC_MSG_CHECKING([if LD -Wl,--version-script works])
  26     save_LDFLAGS="$LDFLAGS"
  27     LDFLAGS="$LDFLAGS -Wl,--version-script=conftest.map"
  28     cat > conftest.map <<EOF
  29 foo
  30 EOF
  31     AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
  32                    [accepts_syntax_errors=yes], [accepts_syntax_errors=no])
  33     if test "$accepts_syntax_errors" = no; then
  34       cat > conftest.map <<EOF
  35 VERS_1 {
  36         global: sym;
  37 };
  38
  39 VERS_2 {
  40         global: sym;
  41 } VERS_1;
  42 EOF
  43       AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
  44                      [have_ld_version_script=yes], [have_ld_version_script=no])
  45     else
  46       have_ld_version_script=no
  47     fi
  48     rm -f conftest.map
  49     LDFLAGS="$save_LDFLAGS"
  50     AC_MSG_RESULT($have_ld_version_script)
  51   fi
  52   AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
  53 ])