stdio: Remove the usage of $(fno-unit-at-a-time) for siglist.c

The siglist.c is built with -fno-toplevel-reorder to avoid compiler
to reorder the compat assembly directives due an assembler
issue [1] (fixed on 2.39).

This patch removes the compiler flags by split the compat symbol
generation in two phases.  First the __sys_siglist and __sys_sigabbrev
without any compat symbol directive is preprocessed to generate an
assembly source code.  This generate assembly is then used as input
on a platform agnostic siglist.S which then creates the compat
definitions.  This prevents compiler to move any compat directive
prior the _sys_errlist definition itself.

Checked on a make check run-built-tests=no on all affected ABIs.

Reviewed-by: Fangrui Song <maskray@google.com>

1 files changed, 5 insertions, 2 deletions

diff --git a/sysdeps/unix/sysv/linux/siglist-compat.c b/sysdeps/unix/sysv/linux/siglist-compat.h
index cbc77289c0..2a9801276d 100644
--- a/sysdeps/unix/sysv/linux/siglist-compat.c
+++ b/sysdeps/unix/sysv/linux/siglist-compat.h
@@ -16,7 +16,10 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <siglist-compat.h>
+#include <siglist-compat-def.h>
+/* To get _NSIG definition.  */
+#define _SIGNAL_H
+#include <bits/signum-generic.h>
 
 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
 DEFINE_COMPAT_SIGLIST (32, GLIBC_2_0)
@@ -27,5 +30,5 @@ DEFINE_COMPAT_SIGLIST (64, GLIBC_2_1)
 #endif
 
 #if SHLIB_COMPAT (libc, GLIBC_2_3_3, GLIBC_2_32)
-DEFINE_COMPAT_SIGLIST (NSIG, GLIBC_2_3_3)
+DEFINE_COMPAT_SIGLIST (_NSIG, GLIBC_2_3_3)
 #endif