SDL: cmake: Print a warning if the libdecor development library is missing (ce68c)

SDL Commits
1 
From ce68c297f0d0484dd26652da7a2b049c453bf3dd Mon Sep 17 00:00:00 2001
From: Frank Praznik <[EMAIL REDACTED]>
Date: Wed, 24 Jun 2026 21:45:03 -0400
Subject: [PATCH] cmake: Print a warning if the libdecor development library is
 missing

libdecor is required for window decorations on Wayland when the toplevel decoration protocol is not supported, such as on GNOME and Weston. Warn if the development library can't be found, unless it was explicitly disabled.

(cherry picked from commit 607eb5206ee9c377c8f970e379ebc9db154c5bc4)
---
 cmake/sdlchecks.cmake | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/cmake/sdlchecks.cmake b/cmake/sdlchecks.cmake
index 99d9251395b5c..8c837c49ad684 100644
--- a/cmake/sdlchecks.cmake
+++ b/cmake/sdlchecks.cmake
@@ -751,7 +751,9 @@ macro(CheckWayland)
             sdl_link_dependency(libdecor INCLUDES $<TARGET_PROPERTY:PkgConfig::PC_LIBDECOR,INTERFACE_INCLUDE_DIRECTORIES>)
           else()
             sdl_link_dependency(libdecor LIBS PkgConfig::PC_LIBDECOR PKG_CONFIG_PREFIX PC_LIBDECOR PKG_CONFIG_SPECS ${LibDecor_PKG_CONFIG_SPEC})
-            endif()
+          endif()
+        else()
+          message(WARNING "Unable to find the libdecor development library (required for window decorations on GNOME and Weston)")
         endif()
       endif()