add libobjc2 CMake patch

Author: hmelder

patches/libobjc2-fix-blocksrt-detection.patch

@@ -0,0 +1,24 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 3f07337..32d009c 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -245,6 +245,7 @@ else ()
+ 	find_library(BLOCKS_RUNTIME_LIBRARY BlocksRuntime)
+ 	if (BLOCKS_RUNTIME_LIBRARY)
+ 		set(CMAKE_REQUIRED_LIBRARIES ${BLOCKS_RUNTIME_LIBRARY})
++    set(CMAKE_REQUIRED_INCLUDES ${CMAKE_INSTALL_PREFIX}/include)
+ 		check_symbol_exists(_Block_use_RR2 "Block_private.h" HAVE_BLOCK_USE_RR2)
+ 		if (HAVE_BLOCK_USE_RR2)
+ 			add_definitions(-DHAVE_BLOCK_USE_RR2)
+@@ -271,6 +272,11 @@ if (WIN32 AND NOT MINGW)
+ endif()
+ 
+ target_link_libraries(objc PRIVATE tsl::robin_map)
++target_include_directories(
++    objc
++    PRIVATE
++    ${CMAKE_INSTALL_PREFIX}/include
++)
+ 
+ set_target_properties(objc PROPERTIES
+ 	LINKER_LANGUAGE C