CMake: Add helper to swiftify imported properties from dependencies

Works around https://gitlab.kitware.com/cmake/cmake/-/issues/26195

AK/CMakeLists.txt

@@ -58,6 +58,7 @@ else()
 endif()
 
 find_package(simdutf REQUIRED)
+swizzle_target_properties_for_swift(simdutf::simdutf)
 target_link_libraries(AK PRIVATE simdutf::simdutf)
 
 if (ENABLE_SWIFT)

Meta/CMake/Swift/swift-settings.cmake

@@ -22,3 +22,16 @@ add_compile_options("SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xcc -std=c++23 -cxx-inte
 if (APPLE)
     set(CMAKE_Swift_COMPILER_TARGET "${CMAKE_SYSTEM_PROCESSOR}-apple-macosx${CMAKE_OSX_DEPLOYMENT_TARGET}")
 endif()
+
+# FIXME: https://gitlab.kitware.com/cmake/cmake/-/issues/26195
+# For now, we'll just manually massage the flags.
+function(swizzle_target_properties_for_swift target_name)
+    get_property(compile_options TARGET ${target_name} PROPERTY INTERFACE_COMPILE_OPTIONS)
+    set(munged_properties "")
+    foreach(property IN LISTS compile_options)
+        set(cxx_property "$<$<COMPILE_LANGUAGE:C,CXX,ASM>:${property}>")
+        set(swift_property "SHELL:$<$<COMPILE_LANGUAGE:Swift>:-Xcc ${property}>")
+        list(APPEND munged_properties "${cxx_property}" "${swift_property}")
+    endforeach()
+    set_property(TARGET ${target_name} PROPERTY INTERFACE_COMPILE_OPTIONS ${munged_properties})
+endfunction()

Meta/CMake/utils.cmake

@@ -252,3 +252,8 @@ function(add_lagom_library_install_rules target_name)
         INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
     )
 endfunction()
+
+if (NOT COMMAND swizzle_target_properties_for_swift)
+    function(swizzle_target_properties_for_swift target)
+    endfunction()
+endif()