Merge pull request swiftlang#39296 from DougGregor/source-compat-install-clang

Author: DougGregor

utils/build-presets.ini

@@ -2522,7 +2522,7 @@ darwin-toolchain-display-name-short=Swift Development Snapshot
 darwin-toolchain-display-name=Swift Development Snapshot
 darwin-toolchain-name=swift-DEVELOPMENT-SNAPSHOT
 darwin-toolchain-version=3.999.999
-llvm-install-components=libclang;libclang-headers;dsymutil
+llvm-install-components=clang;clang-resource-headers;compiler-rt;libclang;libclang-headers;dsymutil
 swift-install-components=back-deployment;compiler;clang-builtin-headers;stdlib;sdk-overlay;license;sourcekit-xpc-service;swift-remote-mirror;swift-remote-mirror-headers
 symbols-package=%(symbols_package)s
 install-symroot=%(install_symroot)s