include of non-modular header inside framework module 'WebGPU_Private.DDModelTypes'

https://bugs.webkit.org/show_bug.cgi?id=305669
rdar://168311619

Reviewed by Elliott Williams.

Pass -isystem so the build finds the correct header files.

* Source/WebGPU/Configurations/WebGPU.xcconfig:

Canonical link: https://commits.webkit.org/306015@main

Author: mwyrzykowski

Source/WebGPU/Configurations/WebGPU.xcconfig

@@ -71,7 +71,7 @@ WK_ENABLE_MODULE_VERIFIER_ENABLE_WEBGPU_SWIFT = YES;
 MODULE_VERIFIER_SUPPORTED_LANGUAGES = objective-c objective-c++;
 MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = gnu23 gnu++23;
 MODULE_VERIFIER_KIND = builtin;
-OTHER_MODULE_VERIFIER_FLAGS = -- -I$(BUILT_PRODUCTS_DIR)$(WK_LIBRARY_HEADERS_FOLDER_PATH) -I$(WK_ADDITIONAL_SDKS)$(WK_LIBRARY_HEADERS_FOLDER_PATH);
+OTHER_MODULE_VERIFIER_FLAGS = -- -I$(BUILT_PRODUCTS_DIR)$(WK_LIBRARY_HEADERS_FOLDER_PATH) -I$(WK_ADDITIONAL_SDKS)$(WK_LIBRARY_HEADERS_FOLDER_PATH) -isystem $(SDKROOT)$(WK_LIBRARY_HEADERS_FOLDER_PATH);
 
 SUPPORTS_TEXT_BASED_API = $(OVERRIDE_SUPPORTS_TEXT_BASED_API:default=YES);
 TAPI_USE_SRCROOT = YES;