cmake: allow find_package from build directory (requires CMake 3.26)

CMakeLists.txt

@@ -78,6 +78,12 @@ if (LIBC_IS_GLIBC AND CMAKE_SIZEOF_VOID_P EQUAL 4)
     target_compile_definitions(sdl-build-options INTERFACE "_FILE_OFFSET_BITS=64")
 endif()
 
+if(CMAKE_VERSION VERSION_LESS "3.26")
+  set(build_local_interface "BUILD_INTERFACE")
+else()
+  set(build_local_interface "BUILD_LOCAL_INTERFACE")
+endif()
+
 # Increment this if there is an incompatible change - but if that happens,
 # we should rename the library from SDL3 to SDL4, at which point this would
 # reset to 0 anyway.
@@ -3231,9 +3237,9 @@ if(SDL_SHARED)
   )
   target_link_libraries(SDL3 PUBLIC $<TARGET_NAME:SDL3::Headers>)
   # This picks up all the compiler options and such we've accumulated up to here.
-  target_link_libraries(SDL3 PRIVATE $<BUILD_INTERFACE:sdl-build-options>)
+  target_link_libraries(SDL3 PRIVATE $<${build_local_interface}:sdl-build-options>)
-  target_link_libraries(SDL3 PRIVATE $<BUILD_INTERFACE:sdl-shared-build-options>)
+  target_link_libraries(SDL3 PRIVATE $<${build_local_interface}:sdl-shared-build-options>)
-  target_link_libraries(SDL3 PRIVATE $<BUILD_INTERFACE:sdl-global-options>)
+  target_link_libraries(SDL3 PRIVATE $<${build_local_interface}:sdl-global-options>)
   if(MINGW OR CYGWIN)
     if(NOT CMAKE_VERSION VERSION_LESS "3.13")
       target_link_options(SDL3 PRIVATE -static-libgcc)
@@ -3275,8 +3281,8 @@ if(SDL_STATIC)
   )
   target_link_libraries(SDL3-static PUBLIC $<TARGET_NAME:SDL3::Headers>)
   # This picks up all the compiler options and such we've accumulated up to here.
-  target_link_libraries(SDL3-static PRIVATE $<BUILD_INTERFACE:sdl-build-options>)
+  target_link_libraries(SDL3-static PRIVATE $<${build_local_interface}:sdl-build-options>)
-  target_link_libraries(SDL3-static PRIVATE $<BUILD_INTERFACE:sdl-global-options>)
+  target_link_libraries(SDL3-static PRIVATE $<${build_local_interface}:sdl-global-options>)
   # Use `Compatible Interface Properties` to allow consumers to enforce a shared/static library
   set_property(TARGET SDL3-static PROPERTY INTERFACE_SDL3_SHARED FALSE)
   set_property(TARGET SDL3-static APPEND PROPERTY COMPATIBLE_INTERFACE_BOOL SDL3_SHARED)
@@ -3297,7 +3303,7 @@ if(SDL_TEST)
   file(GLOB TEST_SOURCES ${SDL3_SOURCE_DIR}/src/test/*.c)
   add_library(SDL3_test STATIC ${TEST_SOURCES})
   add_library(SDL3::SDL3_test ALIAS SDL3_test)
-  target_link_libraries(SDL3_test PRIVATE $<BUILD_INTERFACE:sdl-global-options>)
+  target_link_libraries(SDL3_test PRIVATE $<${build_local_interface}:sdl-global-options>)
   set_target_properties(SDL3_test PROPERTIES
       EXPORT_NAME SDL3_test)
   if(APPLE)
@@ -3320,8 +3326,6 @@ if(SDL_TEST)
   target_link_libraries(SDL3_test PRIVATE ${EXTRA_TEST_LIBS})
 endif()
 
-if(NOT SDL_DISABLE_INSTALL)
-
 ##### Configure installation folders #####
 
 if(WINDOWS AND NOT MINGW)
@@ -3382,6 +3386,37 @@ if(NOT SDL_DISABLE_INSTALL)
   set(SDL_SDLtest_INSTALL_CMAKEFILENAME "SDL3testTargets.cmake")
   endif()
 
+if(CMAKE_VERSION VERSION_LESS "3.26")
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/SDL3Targets.cmake" [[message(FATAL_ERROR "find_package(SDL3) using the SDL3 build directory not supported for CMake versions older then 3.26.")]])
+else()
+  export(TARGETS SDL3_Headers NAMESPACE "SDL3::" FILE "SDL3headersTargets.cmake")
+
+  if(SDL_SHARED)
+    export(TARGETS SDL3 NAMESPACE "SDL3::" FILE "SDL3Targets.cmake")
+  endif()
+
+  if(SDL_STATIC)
+    export(TARGETS SDL3-static NAMESPACE "SDL3::" FILE "SDL3staticTargets.cmake")
+  endif()
+
+  if(SDL_TEST)
+    export(TARGETS SDL3_test NAMESPACE "SDL3::" FILE "SDL3testTargets.cmake")
+  endif()
+endif()
+
+configure_file("cmake/sdlfind.cmake" "sdlfind.cmake" COPYONLY)
+
+include(CMakePackageConfigHelpers)
+configure_package_config_file(cmake/SDL3Config.cmake.in SDL3Config.cmake
+  PATH_VARS CMAKE_INSTALL_PREFIX
+  INSTALL_DESTINATION "${SDL_SDL_INSTALL_CMAKEDIR}"
+)
+write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/SDL3ConfigVersion.cmake"
+  COMPATIBILITY AnyNewerVersion
+)
+
+if(NOT SDL_DISABLE_INSTALL)
+
   ##### sdl3.pc #####
 
   # Clean up variables for sdl3.pc
@@ -3452,16 +3487,7 @@ if(NOT SDL_DISABLE_INSTALL)
     )
   endif()
 
-  ##### CMake Export files #####
+  ##### Install CMake Targets #####
-
-  include(CMakePackageConfigHelpers)
-  configure_package_config_file(cmake/SDL3Config.cmake.in SDL3Config.cmake
-    PATH_VARS CMAKE_INSTALL_PREFIX
-    INSTALL_DESTINATION "${SDL_SDL_INSTALL_CMAKEDIR}"
-  )
-  write_basic_package_version_file("${CMAKE_CURRENT_BINARY_DIR}/SDL3ConfigVersion.cmake"
-    COMPATIBILITY AnyNewerVersion
-  )
 
   install(EXPORT SDL3headersTargets
     FILE "SDL3headersTargets.cmake"

cmake/sdlfind.cmake

@@ -1,9 +1,8 @@
-
 macro(sdlFindALSA)
   find_package(ALSA MODULE)
-  if(ALSA_FOUND AND (NOT TARGET ALSA::ALSA) )
+  if(ALSA_FOUND AND NOT TARGET ALSA::ALSA)
     add_Library(ALSA::ALSA UNKNOWN IMPORTED)
-    set_property(TARGET ALSA::ALSA PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${ALSA_INCLUDE_DIRS})
+    set_property(TARGET ALSA::ALSA PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${ALSA_INCLUDE_DIRS}")
-    set_property(TARGET ALSA::ALSA APPEND PROPERTY IMPORTED_LOCATION ${ALSA_LIBRARY})
+    set_property(TARGET ALSA::ALSA APPEND PROPERTY IMPORTED_LOCATION "${ALSA_LIBRARY}")
   endif()
 endmacro()