Ada support: a community CodeQL extractor, and using it from code scanning

[peter-villadsen]

I maintain codeql-ada (https://github.com/peter-villadsen/codeql-ada, MIT), a CodeQL
extractor and QL library for Ada:

• Extractor built on AdaCore's Libadalang; build mode none, reads GNAT .gpr
  projects; Linux x86-64 tarball per release, plus a container image
  (ghcr.io/peter-villadsen/codeql-ada).
• Library pack peter-villadsen/ada-all and query pack peter-villadsen/ada-queries on
  GHCR. The library follows the Java library's design (AST, the shared
  ControlFlowGraph and SSA libraries, data flow with taint tracking).
• Tested with CodeQL CLI 2.25.6.

Ada is common in safety- and security-critical code, and there is no CodeQL support for
it today. Two requests:

1. github/codeql-action rejects languages: ada ("Unrecognized language"), so users
   have to run the CLI in shell steps and use only upload-sarif. Could the action
   accept a language provided by an extractor on the search path?
2. Would GitHub consider listing community-maintained extractors (with a clear
   "not supported by GitHub" note) on "Supported languages and frameworks", or
   somewhere linked from it?

I'd welcome feedback on the extractor and library, and I'm open to discussing what it
would take for Ada to become an officially supported language.

Peter Villadsen