Build of v0.9 fails on Debian 11 / Devuan 4 - files missing

[eyalroz]

Describe the bug

CMake build configuration succeeds, yet build fails, with errors about missing files:

/usr/local/src/cling-0.9/tools/plugins/example/DemoPlugin.cpp:10:10: fatal error: clang/Frontend/FrontendPluginRegistry.h: No such file or directory
   10 | #include "clang/Frontend/FrontendPluginRegistry.h"

and

In file included from /usr/local/src/cling-0.9/lib/Interpreter/ASTTransformer.cpp:10:
/usr/local/src/cling-0.9/lib/Interpreter/ASTTransformer.h:15:10: fatal error: clang/AST/Decl.h: No such file or directory
   15 | #include "clang/AST/Decl.h" // for Result(Decl)

etc.

Expected behavior

Build configuration can fail if there's something missing on the system, but if it succeeded - so should the build.

To Reproduce

1. Install Devuan Chimaera / Debian Bullseye.
2. Download v0.9 sources
3. Run CMake
4. (Install any missing dependencies; on my system they are likely present already)
5. Run cmake --build /path/to/build/dir

Setup

1. Cling version: 0.9
2. Operating system: Devuan Chimaera GNU/Linux
3. How you obtained Cling: From github.

Additional context

You guys should really offer a Debian APT repository with builds for at least the stable release, hopefully testing and unstable too.