SDL: Fix Debug-only builds with CMake

From 87ac373493fa9ff8e0277c60d545bfcd5f210844 Mon Sep 17 00:00:00 2001
From: Daniel Gibson <[EMAIL REDACTED]>
Date: Wed, 6 Oct 2021 03:39:59 +0200
Subject: [PATCH] Fix Debug-only builds with CMake

"get_filename_component(SDL2_LIBDIR ${sdl2implib} PATH)" failed if
sdl2implib was set from sdl2implibdbg instead of ${sdl2implibdbg}

Thanks to seyuup from the SDL Discourse for pointing this out.
---
 SDL2Config.cmake | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/SDL2Config.cmake b/SDL2Config.cmake
index e24fa7975a..7c31469f12 100644
--- a/SDL2Config.cmake
+++ b/SDL2Config.cmake
@@ -68,10 +68,10 @@ if( sdl2implib AND sdl2mainimplib AND sdl2implibdbg AND sdl2mainimplibdbg )
 	set(SDL2_LIBRARIES $<IF:$<CONFIG:Debug>,${sdl2mainimplibdbg},${sdl2mainimplib}>   $<IF:$<CONFIG:Debug>,${sdl2implibdbg},${sdl2implib}>)
 else()
 	if( (NOT sdl2implib) AND sdl2implibdbg ) # if we only have a debug version of the lib
-		set(sdl2implib sdl2implibdbg)
+		set(sdl2implib ${sdl2implibdbg})
 	endif()
 	if( (NOT sdl2mainimplib) AND sdl2mainimplibdbg ) # if we only have a debug version of the lib
-		set(sdl2mainimplib sdl2mainimplibdbg)
+		set(sdl2mainimplib ${sdl2mainimplibdbg})
 	endif()
 
 	if( sdl2implib AND sdl2mainimplib )