Dependencies: emit warning instead of error if the Swift toolchain can't support VALIDATE_MODULE_DEPENDENCIES to match clang#669

mirza-garibovic merged 1 commit intoswiftlang:mainswiftlang/swift-build:mainfrom

mirza-garibovic:mod-deps-warningmirza-garibovic/swift-build:mod-deps-warningCopy head branch name to clipboard