[clang] [clang][InstallAPI] Introduce basic driver to write out tbd files (PR #81571)

[Juergen Ributzka via cfe-commits]

================
@@ -804,4 +804,7 @@ def warn_android_unversioned_fallback : Warning<
 
 def err_drv_triple_version_invalid : Error<
   "version '%0' in target triple '%1' is invalid">;
+
+def err_drv_installapi_unsupported : Error<
+  "the clang compiler does not support '%0' for InstallAPI">;
----------------
ributzka wrote:

Nit: The clang compiler is implied, so the error message could be shortened to: "InstallAPI is not supported for '%0'"

https://github.com/llvm/llvm-project/pull/81571