m4/ld-version-script.m4

   1 # ld-version-script.m4 serial 4
   2 dnl Copyright (C) 2008-2015 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=$enableval],
  24     [AC_CACHE_CHECK([if LD -Wl,--version-script works],
  25        [gl_cv_sys_ld_version_script],
  26        [gl_cv_sys_ld_version_script=no
  27         save_LDFLAGS=$LDFLAGS
  28         LDFLAGS="$LDFLAGS -Wl,--version-script=conftest.map"
  29         echo foo >conftest.map
  30         AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
  31           [],
  32           [cat > conftest.map <<EOF
  33 VERS_1 {
  34         global: sym;
  35 };
  36
  37 VERS_2 {
  38         global: sym;
  39 } VERS_1;
  40 EOF
  41            AC_LINK_IFELSE([AC_LANG_PROGRAM([], [])],
  42              [gl_cv_sys_ld_version_script=yes])])
  43         rm -f conftest.map
  44         LDFLAGS=$save_LDFLAGS])
  45      have_ld_version_script=$gl_cv_sys_ld_version_script])
  46   AM_CONDITIONAL([HAVE_LD_VERSION_SCRIPT],
  47     [test "$have_ld_version_script" = yes])
  48 ])