swift

30ecaeb4 - [ClangImporter] `-Xclang -fbuiltin-headers-in-system-modules` is being passed when it shouldn't

[ClangImporter] `-Xclang -fbuiltin-headers-in-system-modules` is being passed when it shouldn't We were accidentally setting `requiresBuiltinHeadersInSystemModules` because the `else` here gets executed for things that are not WASI or Musl. Fix by making it conditional. rdar://128219177