package/gcc: disable split-stack for non-thread builds for gcc powerpc spe

The toolchain for powerpc spe can use uClibc-ng without thread support.
So we need the same fix as commit [1].

[1] fff68f75b3

Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/gcc/8.4.0/0004-disable-split-stack-for-non-thread-builds.patch

@@ -0,0 +1,26 @@
+From 1ddcb4870533af1b71b6afb75b8f2b271fd88eb4 Mon Sep 17 00:00:00 2001
+From: Waldemar Brodkorb <wbx@openadk.org>
+Date: Mon, 25 Jul 2022 00:29:55 +0200
+Subject: [PATCH] disable split-stack for non-thread builds
+
+Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
+[Romain: convert to git format]
+Signed-off-by: Romain Naour <romain.naour@smile.fr>
+---
+ libgcc/config/t-stack | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/libgcc/config/t-stack b/libgcc/config/t-stack
+index cc0366b4cd8..f3f97e86d60 100644
+--- a/libgcc/config/t-stack
++++ b/libgcc/config/t-stack
+@@ -1,4 +1,6 @@
+ # Makefile fragment to provide generic support for -fsplit-stack.
+ # This should be used in config.host for any host which supports
+ # -fsplit-stack.
++ifeq ($(enable_threads),yes)
+ LIB2ADD_ST += $(srcdir)/generic-morestack.c $(srcdir)/generic-morestack-thread.c
++endif
+-- 
+2.34.3
+