summaryrefslogtreecommitdiffstats
path: root/m4/lib-ignore.m4
diff options
context:
space:
mode:
Diffstat (limited to 'm4/lib-ignore.m4')
-rw-r--r--m4/lib-ignore.m4115
1 files changed, 115 insertions, 0 deletions
diff --git a/m4/lib-ignore.m4 b/m4/lib-ignore.m4
new file mode 100644
index 0000000..1b7703f
--- /dev/null
+++ b/m4/lib-ignore.m4
@@ -0,0 +1,115 @@
+# If possible, ignore libraries that are not depended on.
+
+dnl Copyright (C) 2006, 2009-2020 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.
+
+# gl_IGNORE_UNUSED_LIBRARIES
+# --------------------------
+# Determines the option to be passed to the C/C++/Fortran compiler, so that it
+# omits unused libraries.
+# Example (on Solaris):
+# $ cc foo.c -lnsl; ldd ./a.out
+# libnsl.so.1 => /lib/libnsl.so.1
+# libc.so.1 => /lib/libc.so.1
+# libmp.so.2 => /lib/libmp.so.2
+# libmd.so.1 => /lib/libmd.so.1
+# libscf.so.1 => /lib/libscf.so.1
+# libdoor.so.1 => /lib/libdoor.so.1
+# libuutil.so.1 => /lib/libuutil.so.1
+# libgen.so.1 => /lib/libgen.so.1
+# libm.so.2 => /lib/libm.so.2
+# $ cc foo.c -lnsl -Wl,-z,ignore; ldd ./a.out
+# libc.so.1 => /lib/libc.so.1
+# libm.so.2 => /lib/libm.so.2
+#
+# Note that the option works only for the C compiler, not for the C++
+# compiler:
+# - Sun C likes '-Wl,-z,ignore'.
+# '-Qoption ld -z,ignore' is not accepted.
+# '-z ignore' is accepted but has no effect.
+# - Sun C++ and Sun Fortran like '-Qoption ld -z,ignore'.
+# '-Wl,-z,ignore' is not accepted.
+# '-z ignore' is accepted but has no effect.
+#
+# Sets and substitutes a variable that depends on the current language:
+# - IGNORE_UNUSED_LIBRARIES_CFLAGS for C
+# - IGNORE_UNUSED_LIBRARIES_CXXFLAGS for C++
+# - IGNORE_UNUSED_LIBRARIES_FFLAGS for Fortran
+#
+# Note that the option works only for direct invocation of the compiler, not
+# through libtool: When libtool is used to create a shared library, it will
+# honor and translate '-Wl,-z,ignore' to '-Qoption ld -z -Qoption ld ignore'
+# if needed, but it will drop a '-Qoption ld -z,ignore' on the command line.
+#
+AC_DEFUN([gl_IGNORE_UNUSED_LIBRARIES],
+[
+ AC_CACHE_CHECK([for []_AC_LANG[] compiler flag to ignore unused libraries],
+ [gl_cv_prog_[]_AC_LANG_ABBREV[]_ignore_unused_libraries],
+ [gl_cv_prog_[]_AC_LANG_ABBREV[]_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
+ # <https://lists.gnu.org/r/bug-gnulib/2006-06/msg00131.html>.
+ LIBS="$LIBS -lm"
+ # Use long option sequences like '-z ignore' to test for the feature,
+ # to forestall problems with linkers that have -z, -i, -g, -n, etc. flags.
+ # GCC + binutils likes '-Wl,--as-needed'.
+ # GCC + Solaris ld likes '-Wl,-z,ignore'.
+ # Sun C likes '-Wl,-z,ignore'. '-z ignore' is accepted but has no effect.
+ # Don't try bare '--as-needed'; nothing likes it and the HP-UX 11.11
+ # native cc issues annoying warnings and then ignores it,
+ # which would cause us to incorrectly conclude that it worked.
+ for gl_flags in _gl_IGNORE_UNUSED_LIBRARIES_OPTIONS
+ do
+ LDFLAGS="$gl_flags $LDFLAGS"
+ AC_LINK_IFELSE([AC_LANG_PROGRAM()],
+ [gl_cv_prog_[]_AC_LANG_ABBREV[]_ignore_unused_libraries=$gl_flags])
+ LDFLAGS=$gl_saved_ldflags
+ test "$gl_cv_prog_[]_AC_LANG_ABBREV[]_ignore_unused_libraries" != none &&
+ break
+ done
+ LIBS=$gl_saved_libs
+ ])
+ IGNORE_UNUSED_LIBRARIES_[]_AC_LANG_PREFIX[]FLAGS=
+ if test "$gl_cv_prog_[]_AC_LANG_ABBREV[]_ignore_unused_libraries" != none; then
+ IGNORE_UNUSED_LIBRARIES_[]_AC_LANG_PREFIX[]FLAGS="$gl_cv_prog_[]_AC_LANG_ABBREV[]_ignore_unused_libraries"
+ fi
+ AC_SUBST([IGNORE_UNUSED_LIBRARIES_]_AC_LANG_PREFIX[FLAGS])
+])
+
+# _gl_IGNORE_UNUSED_LIBRARIES_OPTIONS
+# -----------------------------------
+# Expands to the language dependent options to be tried.
+AC_DEFUN([_gl_IGNORE_UNUSED_LIBRARIES_OPTIONS],
+[_AC_LANG_DISPATCH([$0], _AC_LANG, $@)])
+
+# _gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(C)
+# --------------------------------------
+m4_define([_gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(C)],
+[ '-Wl,--as-needed' \
+ '-Wl,-z,ignore' \
+ '-z ignore'
+])
+
+# _gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(C++)
+# ----------------------------------------
+m4_define([_gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(C++)],
+[ '-Wl,--as-needed' \
+ '-Qoption ld -z,ignore' \
+ '-Wl,-z,ignore' \
+ '-z ignore'
+])
+
+# _gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(Fortran 77)
+# -----------------------------------------------
+m4_copy([_gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(C++)],
+ [_gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(Fortran 77)])
+
+# _gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(Fortran)
+# --------------------------------------------
+m4_copy([_gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(Fortran 77)],
+ [_gl_IGNORE_UNUSED_LIBRARIES_OPTIONS(Fortran)])