Avoid asm.S usage on various Linux architectures

Resolves: RHEL-31139

avoid-asm.patch

@@ -0,0 +1,39 @@
+From 95b957d5381ae6b313333f50bb941e9970d55127 Mon Sep 17 00:00:00 2001
+From: Christian Hergert <chergert@redhat.com>
+Date: Wed, 12 Jun 2024 11:17:52 -0700
+Subject: [PATCH] build: avoid asm.S on general Linux when possible
+
+We only use asm.S when on mips when we're on Linux. Removing this means
+for the other Linux cases means the compiler can automatically enable some
+features we might want like CET for indirect branches.
+---
+ src/meson.build | 10 +++++++++-
+ 1 file changed, 9 insertions(+), 1 deletion(-)
+
+diff --git a/src/meson.build b/src/meson.build
+index 2967968..4a106a1 100644
+--- a/src/meson.build
++++ b/src/meson.build
+@@ -91,10 +91,18 @@ if host_machine.system() != 'windows'
+   # Not really used on Windows now, see also
+   # https://github.com/mesonbuild/meson/issues/4366
+   libdex_sources += [
+-    'asm.S',
+     'dex-unix-signal.c',
+     'dex-ucontext.c',
+   ]
++
++  # If we're on Linux and mips we might still need asm.S.
++  # But otherwise linux can do it all without any custom
++  # assembler. Failure to do this might result in CET being
++  # disabled for the process by GCC.
++  if host_machine.system() != 'linux' or host_machine.cpu_family() == 'mips'
++    libdex_sources += ['asm.S']
++  endif
++
+   libdex_headers += ['dex-unix-signal.h']
+ endif
+ 
+-- 
+2.45.1
+

libdex.spec

@@ -7,6 +7,8 @@ License: LGPL-2.1-or-later
 URL:     https://gitlab.gnome.org/GNOME/libdex
 Source0: https://download.gnome.org/sources/libdex/0.6/%{name}-%{version}.tar.xz
 
+Patch0:        avoid-asm.patch
+
 BuildRequires: /usr/bin/vapigen
 BuildRequires: gcc
 BuildRequires: gi-docgen