xhpast: Skip -minline-all-stringops on non-x86 architectures

Summary:
-minline-all-stringops is a x86 only option, and will not work on other architectures.
Thus remove it for other architectures.

Test Plan:
Build on other architectures. I cherry-picked this to AOSC OS packaging and it has built successfully on amd64, arm64, riscv64, ppc64el, loongson3, loongarch64.

Or, manually run this script and see that - only on x86 - it prints the mentioned flag:

    php support/xhpast/bin/xhpast-generate-release-cppflags.php

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: aklapper, tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D25871

support/xhpast/Makefile

@@ -8,7 +8,7 @@ ifdef DEBUG
 	CPPFLAGS   += -ggdb -DDEBUG
 	FLEXFLAGS  += --debug
 else
-	CPPFLAGS  += -O3 -minline-all-stringops
+	CPPFLAGS   += -O3 $(shell ./bin/xhpast-generate-release-cppflags.php)
 endif
 
 ifdef PROFILE

support/xhpast/bin/xhpast-generate-release-cppflags.php

@@ -0,0 +1,15 @@
+#!/usr/bin/env php
+<?php
+
+// $arcanist_root = dirname(dirname(dirname(dirname(__FILE__))));
+// require_once $arcanist_root.'/support/init/init-script.php';
+
+$cppflags = '';
+$arch = php_uname('m');
+
+if ($arch == 'i386' || $arch == 'x86_64') {
+  $cppflags .= ' -minline-all-stringops ';
+}
+
+echo $cppflags;
+echo "\n";