Re: [bug-gnulib] gettext: -lintl if necessary

[Paul Eggert]

Bruno Haible <address@hidden> writes:

> Simon Josefsson wrote:
>> The gettext module brings in the proper -I's to make gettext calls
>> work, but doesn't bring in the library.
>
> This is normal. We specify the needed libraries for each program and
> for each shared library separately. So that, for example, in coreutils
> only those programs are linked to librt and libpthread that need it;
> only those programs are linked to libm that need it; etc. - although
> these needs arise through gnulib modules.

That's longstanding coreutils practice, but it's a maintenance hassle
and in coreutils CVS we're using a new gl_IGNORE_UNUSED_LIBRARIES
macro (defined in m4/lib-ignore.m4) that tells the linker to omit
references to libraries that are not actually used (this is the '-z
ignore' option of the Solaris linker).

At some point I was going to propose to move this into gnulib.

Here's the source code, to save you the hassle of looking it up.


# 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=$LDFLAGS
     # Use long option sequences like '-z ignore' to test for the feature,
     # to forestall problems with linkers that have -z, -i, -g, -n, etc. flags.
     for gl_flags in '-Wl,-z,ignore' '-z ignore'; do
       LDFLAGS="$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])

  test "$gl_cv_ignore_unused_libraries" != none &&
    LDFLAGS="$LDFLAGS $gl_cv_ignore_unused_libraries"
])