SDL: Make sdl2-config prefixes configurable again

From 12cc636c8f6d076c941a5d7ba81448f2c4fcf1e6 Mon Sep 17 00:00:00 2001
From: Tim Schumacher <[EMAIL REDACTED]>
Date: Sat, 21 May 2022 23:33:31 +0200
Subject: [PATCH] Make sdl2-config prefixes configurable again

The installation prefix ended up being hard-coded into the
`sdl2-config` script after the placeholders were accidentally removed
in 6956f4aa1982b66b234026b46f7bb2dd44c67894.
---
 CMakeLists.txt | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8e2832fa032..1ac60d07ce0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2694,9 +2694,9 @@ if(NOT WINDOWS OR CYGWIN OR MINGW)
   set(prefix ${CMAKE_INSTALL_PREFIX})
 
   set(exec_prefix "\${prefix}")
-  set(libdir "${CMAKE_INSTALL_FULL_LIBDIR}")
-  set(bindir "${CMAKE_INSTALL_FULL_BINDIR}")
-  set(includedir "${CMAKE_INSTALL_FULL_INCLUDEDIR}")
+  set(libdir "\${exec_prefix}/${CMAKE_INSTALL_LIBDIR}")
+  set(bindir "\${exec_prefix}/${CMAKE_INSTALL_BINDIR}")
+  set(includedir "\${prefix}/${CMAKE_INSTALL_INCLUDEDIR}")
   if(SDL_STATIC)
     set(ENABLE_STATIC_TRUE "")
     set(ENABLE_STATIC_FALSE "#")