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Diffstat (limited to 'm4/lib-ignore.m4')
| -rw-r--r-- | m4/lib-ignore.m4 | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/m4/lib-ignore.m4 b/m4/lib-ignore.m4 new file mode 100644 index 0000000..e518f81 --- /dev/null +++ b/m4/lib-ignore.m4 @@ -0,0 +1,43 @@ +# If possible, ignore libraries that are not depended on. + +dnl Copyright (C) 2006 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +dnl Written by Paul Eggert. + +AC_DEFUN([gl_IGNORE_UNUSED_LIBRARIES], +[ + AC_CACHE_CHECK([for flag to ignore unused libraries], + [gl_cv_ignore_unused_libraries], + [gl_cv_ignore_unused_libraries=none + gl_saved_ldflags=$LDFLAGS + gl_saved_libs=$LIBS + # Link with -lm to detect binutils 2.16 bug with --as-needed; see + # <http://lists.gnu.org/archive/html/bug-gnulib/2006-06/msg00131.html>. + LIBS="$LIBS -lm" + # Use long option sequences like '-z ignore' to test for the feature, + # to forestall problems with linkers that have -z, -i, -g, -n, etc. flags. + # GCC + binutils likes '-Wl,--as-needed'. + # GCC + Solaris ld likes '-Wl,-z,ignore'. + # Sun C likes '-z ignore'. + # Don't try bare '--as-needed'; nothing likes it and the HP-UX 11.11 + # native cc issues annoying warnings and then ignores it, + # which would cause us to incorrectly conclude that it worked. + for gl_flags in \ + '-Wl,--as-needed' \ + '-Wl,-z,ignore' \ + '-z ignore' + do + LDFLAGS="$gl_flags $LDFLAGS" + AC_LINK_IFELSE([AC_LANG_PROGRAM()], + [gl_cv_ignore_unused_libraries=$gl_flags]) + LDFLAGS=$gl_saved_ldflags + test "$gl_cv_ignore_unused_libraries" != none && break + done + LIBS=$gl_saved_libs]) + + test "$gl_cv_ignore_unused_libraries" != none && + LDFLAGS="$LDFLAGS $gl_cv_ignore_unused_libraries" +]) |