https://github.com/aranym/aranym/pull/102

From 1a45b77ee2eaabc53fef0794c0e3a64a7c41683e Mon Sep 17 00:00:00 2001
From: Sam James <sam@gentoo.org>
Date: Sun, 19 Mar 2023 02:05:09 +0000
Subject: [PATCH] configure.ac: fix bashisms

configure scripts need to be runnable with a POSIX-compliant /bin/sh.

On many (but not all!) systems, /bin/sh is provided by Bash, so errors
like this aren't spotted. Notably Debian defaults to /bin/sh provided
by dash which doesn't tolerate such bashisms as '=='.

This retains compatibility with bash.
--- a/configure.ac
+++ b/configure.ac
@@ -1714,7 +1714,7 @@ SDL_CFLAGS=
 SDL_LIBS=
 no_sdl=yes
 no_sdl2=yes
-if test "$OS_TYPE" == darwin -a "$WITH_FINK" = no; then
+if test "$OS_TYPE" = darwin -a "$WITH_FINK" = no; then
 	ARANYM_CHECK_FRAMEWORK(SDL, [])
 	if test "$have_framework_SDL" = yes ; then
 		ARANYM_CHECK_FRAMEWORK_LOCATION(SDL)
@@ -1781,7 +1781,7 @@ SDL_LIBS="$SDL_LIBS -lpthread"
 AM_CONDITIONAL([ENABLE_SDL2], test "$enable_sdl2" = yes)
 #
 # SDL2 on macOS needs 10.6 or above
-if test "$enable_sdl2" = yes -a "$OS_TYPE" == darwin; then
+if test "$enable_sdl2" = yes -a "$OS_TYPE" = darwin; then
 	export MACOSX_DEPLOYMENT_TARGET=10.6
 fi
 
-- 
2.40.0