SDL: Revert "cmake: consider X11 as not available when xext.h is not found"

SDL Commits
1 
From ebe561f9165cf61110450c1848c2c19e2d3b7cc0 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Mon, 6 Jan 2025 20:35:09 +0100
Subject: [PATCH] Revert "cmake: consider X11 as not available when xext.h is
 not found"

This reverts commit fe5468799b0a7cd8fbcc42db1328dea9a80420ce.
---
 cmake/sdlchecks.cmake | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/cmake/sdlchecks.cmake b/cmake/sdlchecks.cmake
index 5f2af744e07f8..ac36cfa2d7ed1 100644
--- a/cmake/sdlchecks.cmake
+++ b/cmake/sdlchecks.cmake
@@ -459,7 +459,10 @@ macro(CheckX11)
     find_file(HAVE_XDBE_H NAMES "X11/extensions/Xdbe.h" HINTS "${X_INCLUDEDIR}")
     find_file(HAVE_XEXT_H NAMES "X11/extensions/Xext.h" HINTS "${X_INCLUDEDIR}")
 
-    if(X11_LIB AND HAVE_XEXT_H)
+    if(X11_LIB)
+      if(NOT HAVE_XEXT_H)
+        message_error("Missing Xext.h, maybe you need to install the libxext-dev package?")
+      endif()
 
       set(HAVE_X11 TRUE)
       set(HAVE_SDL_VIDEO TRUE)