sys-devel/m4: avoid invoking autoconf

Normally we'd just eautoreconf, but this is base-system and we cannot
depend on autoconf, so we have to patch the generated files ourselves.
This can go away once the loong fix patch is no longer necessary.

Fixes: 43dd58338d ("sys-devel/m4: fix build on loong")
Closes: https://github.com/gentoo/gentoo/pull/25195
Closes: https://github.com/gentoo/gentoo/pull/25205
Signed-off-by: WANG Xuerui <xen0n@gentoo.org>
Signed-off-by: Sam James <sam@gentoo.org>

sys-devel/m4/files/loong-fix-build.patch

@@ -1,19 +1,23 @@
-From 34add045fd2ec3f1031dee961c4d9cc4285486a7 Mon Sep 17 00:00:00 2001
+[xen0n: this is https://github.com/sunhaiyong1978/CLFS-for-LoongArch/blob/1.0/patches/stack-direction-add-loongarch.patch with line number tweak, and change to generated file added as well.]
 From: Sun Haiyong <youbest@sina.com>
 Date: Tue, 31 Aug 2021 11:11:52 +0800
 Subject: [PATCH] stack-direction: Add support for loongarch CPU
 
 * m4/stack-direction.m4 (SV_STACK_DIRECTION): When the CPU is loongarch,
 set "sv_cv_stack_direction" to "-1" .
----
- m4/stack-direction.m4 | 1 +
- 1 file changed, 1 insertion(+)
-
-diff --git a/m4/stack-direction.m4 b/m4/stack-direction.m4
-index 93287254b..e6c3284ce 100644
 --- a/m4/stack-direction.m4
 +++ b/m4/stack-direction.m4
-@@ -32,6 +32,7 @@ AC_DEFUN([SV_STACK_DIRECTION],
+@@ -31,6 +31,7 @@ AC_DEFUN([SV_STACK_DIRECTION],
+       i?86 | x86_64 | \
+       i860 | \
+       ia64 | \
++      loongarch* | \
+       m32r | \
+       m68* | \
+       m88k | \
+--- a/configure
++++ b/configure
+@@ -46399,6 +46399,7 @@ else $as_nop
        i?86 | x86_64 | \
        i860 | \
        ia64 | \

sys-devel/m4/m4-1.4.19.ebuild

@@ -51,6 +51,16 @@ src_unpack() {
 	default
 }
 
+src_prepare() {
+	default
+
+	# touch generated files after patching m4, to avoid activating maintainer
+	# mode
+	# remove when loong-fix-build.patch is no longer necessary
+	touch ./aclocal.m4 ./lib/config.hin ./configure || die
+	find . -name Makefile.in -exec touch {} + || die
+}
+
 src_configure() {
 	local -a myeconfargs=(
 		--enable-changeword