SDL_image: cmake: use SDLIMAGE_ROOTPROJECT properly

SDL Commits
1 
From d2e1fd9f443af1c47db16bb74484190422df09e9 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <[EMAIL REDACTED]>
Date: Sat, 28 Dec 2024 01:25:03 +0100
Subject: [PATCH] cmake: use SDLIMAGE_ROOTPROJECT properly

---
 CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index aab1a542..dbc9c893 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,7 +33,7 @@ else()
 endif()
 
 # By default, configure in RelWithDebInfo configuration
-if(NOT SDLIMAGE_ROOTPROJECT)
+if(SDLIMAGE_ROOTPROJECT)
     get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
     if(is_multi_config)
         # The first item in CMAKE_CONFIGURATION_TYPES is the default configuration