gnulib-common: prefer _GL_UNUSED over _UNUSED_PARAMETER_ There are more contexts where __attribute__((__unused__)) is useful than just parameter lists. Also, naming the macro _GL_UNUSED fits with the recent addition of _GL_ARG_NONNULL. Preserve the name _UNUSED_PARAMETER_ for backwards-compatible use in external projects. * m4/gnulib-common.m4 (gl_COMMON): Create a more-appropriately named alias for __attribute__((__unused__)). * lib/chown.c: Update client. * lib/fchmodat.c: Likewise. * lib/fts.c: Likewise. * lib/getdate.y: Likewise. * lib/getgroups.c: Likewise. * lib/getopt.c: Likewise. * lib/getugroups.c: Likewise. * lib/mkdir.c: Likewise. * lib/mkfifo.c: Likewise. * lib/mkfifoat.c: Likewise. * lib/mknod.c: Likewise. * lib/mknodat.c: Likewise. * lib/readlink.c: Likewise. * lib/se-context.in.h: Likewise. * lib/se-selinux.in.h: Likewise. * lib/sockets.c: Likewise. * lib/symlink.c: Likewise. * lib/symlinkat.c: Likewise. * lib/unicodeio.c: Likewise. * lib/unistr.h: Likewise. * tests/test-areadlink.c: Likewise. * tests/test-areadlinkat.c: Likewise. * tests/test-filenamecat.c: Likewise. * tests/test-fseeko.c: Likewise. * tests/test-ftello.c: Likewise. * tests/test-getdate.c: Likewise. * tests/test-getgroups.c: Likewise. * tests/test-gethostname.c: Likewise. * tests/test-quotearg.c: Likewise. * tests/test-version-etc.c: Likewise. * tests/test-xalloc-die.c: Likewise. * tests/test-xfprintf-posix.c: Likewise. * tests/test-xprintf-posix.c: Likewise. * tests/test-xvasprintf.c: Likewise. Signed-off-by: Eric Blake <ebb9@byu.net>

--- a/lib/fchmodat.c
+++ b/lib/fchmodat.c
@@ -28,7 +28,7 @@
 # undef lchmod
 # define lchmod lchmod_rpl
 static int
-lchmod (char const *f _UNUSED_PARAMETER_, mode_t m _UNUSED_PARAMETER_)
+lchmod (char const *f _GL_UNUSED, mode_t m _GL_UNUSED)
 {
   errno = ENOSYS;
   return -1;