cmake: don't create relocatable packages by default with non-MSVC too…

…lchains

CMakeLists.txt

@@ -108,6 +108,7 @@ cmake_dependent_option(SDLMIXER_INSTALL "Enable SDL3mixer install target" ${SDLM
 cmake_dependent_option(SDLMIXER_INSTALL_CPACK "Create binary SDL3_mixer archive using CPack" ${SDLMIXER_ROOTPROJECT} "SDLMIXER_INSTALL" OFF)
 cmake_dependent_option(SDLMIXER_INSTALL_MAN "Install man pages for SDL3_mixer" OFF "SDLMIXER_INSTALL" OFF)
 cmake_dependent_option(SDLMIXER_DEPS_SHARED "Load dependencies dynamically" ON PLATFORM_SUPPORTS_SHARED OFF)
+cmake_dependent_option(SDLMIXER_RELOCATABLE "Create relocatable SDL_mixer package" "${MSVC}" SDLMIXER_INSTALL OFF)
 option(SDLMIXER_VENDORED "Use vendored third-party libraries" ${vendored_default})
 option(SDLMIXER_WERROR "Treat warnings as errors" OFF)
 
@@ -1174,9 +1175,13 @@ if(SDLMIXER_INSTALL)
         COMPONENT devel
     )
 
-    file(RELATIVE_PATH SDL_PATH_PREFIX_RELATIVE_TO_PKGCONFIG "${CMAKE_INSTALL_PREFIX}/${SDLMIXER_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}")
+    if(SDLMIXER_RELOCATABLE)
+      file(RELATIVE_PATH SDL_PATH_PREFIX_RELATIVE_TO_PKGCONFIG "${CMAKE_INSTALL_PREFIX}/${SDLMIXER_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}")
+    else()
+      set(SDL_PKGCONFIG_PREFIX "${CMAKE_INSTALL_PREFIX}")
+    endif()
 
     string(JOIN " " PC_REQUIRES ${PC_REQUIRES})
     string(JOIN " " PC_LIBS ${PC_LIBS})