1 2# GCC 4.x -fvisibility=hidden 3 4AC_DEFUN([CHECK_GCC_FVISIBILITY], [ 5 AC_LANG_PUSH([C]) 6 saved_CFLAGS="$CFLAGS" 7 CFLAGS="$saved_CFLAGS -fvisibility=hidden" 8 AC_CACHE_CHECK([whether compiler accepts -fvisibility=hidden], 9 [ac_cv_fvisibility_hidden], AC_COMPILE_IFELSE( 10 [AC_LANG_SOURCE()], 11 [ac_cv_fvisibility_hidden=yes], 12 [ac_cv_fvisibility_hidden=no] 13 )) 14 if test "$ac_cv_fvisibility_hidden" = "yes"; then 15 AC_DEFINE([HAVE_VISIBILITY_HIDDEN], [1], 16 [True if compiler supports -fvisibility=hidden]) 17 AC_SUBST([GCC_FVISIBILITY_HIDDEN], [-fvisibility=hidden]) 18 fi 19 CFLAGS="$saved_CFLAGS" 20 AC_LANG_POP([C]) 21]) 22