SDL_image: configure.ac: fixed an 'enable_stb_image' check

SDL Commits
1 
From 98335ee687423a602c698a7d613ea8b82364c730 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Tue, 10 May 2022 23:33:20 +0300
Subject: [PATCH] configure.ac: fixed an 'enable_stb_image' check

---
 configure    | 2 +-
 configure.ac | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure b/configure
index a7292d5..2062e69 100755
--- a/configure
+++ b/configure
@@ -13927,7 +13927,7 @@ $as_echo "$as_me: WARNING: JXL image loading disabled" >&2;}
     fi
 fi
 
-if test x$enable_png = xyes -a $enable_stb_image != xyes -a x$enable_imageio != xyes; then
+if test x$enable_png = xyes -a x$enable_stb_image != xyes -a x$enable_imageio != xyes; then
 
 pkg_failed=no
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for libpng" >&5
diff --git a/configure.ac b/configure.ac
index aba92b2..1533d59 100644
--- a/configure.ac
+++ b/configure.ac
@@ -382,7 +382,7 @@ if test x$enable_jxl = xyes; then
     fi
 fi
 
-if test x$enable_png = xyes -a $enable_stb_image != xyes -a x$enable_imageio != xyes; then
+if test x$enable_png = xyes -a x$enable_stb_image != xyes -a x$enable_imageio != xyes; then
     PKG_CHECK_MODULES([LIBPNG], [libpng], [dnl
         have_png_hdr=yes
         have_png_lib=yes