From 4aacc4b92ee4abc2e9d71fb1b696761b125bb606 Mon Sep 17 00:00:00 2001
From: Anonymous Maarten <anonymous.maarten@gmail.com>
Date: Mon, 30 Oct 2023 19:50:35 +0100
Subject: [PATCH] cmake: file(RELATIVE_PATH) needs 2 absolute paths

---
 cmake/sdltargets.cmake | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/cmake/sdltargets.cmake b/cmake/sdltargets.cmake
index 46496239e..d4fe91375 100644
--- a/cmake/sdltargets.cmake
+++ b/cmake/sdltargets.cmake
@@ -332,6 +332,9 @@ function(configure_sdl3_pc)
   endif()
 
   # Calculate prefix relative to location of sdl3.pc
+  if(NOT IS_ABSOLUTE "${CMAKE_INSTALL_PREFIX}")
+    set(CMAKE_INSTALL_PREFIX "${CMAKE_BINARY_DIR}/${CMAKE_INSTALL_PREFIX}")
+  endif()
   file(RELATIVE_PATH SDL_PATH_PREFIX_RELATIVE_TO_PKGCONFIG "${CMAKE_INSTALL_PREFIX}/${SDL_PKGCONFIG_INSTALLDIR}" "${CMAKE_INSTALL_PREFIX}")
   string(REGEX REPLACE "[/]+$" "" SDL_PATH_PREFIX_RELATIVE_TO_PKGCONFIG "${SDL_PATH_PREFIX_RELATIVE_TO_PKGCONFIG}")
   set(SDL_PKGCONFIG_PREFIX "\${pcfiledir}/${SDL_PATH_PREFIX_RELATIVE_TO_PKGCONFIG}")