Support for LLDB in unit test.

[Yrds]

I've been using meson for 1 year and it's been an amazing experience. But now I'm changing some of my projects to clang/lldb.

My previous setup uses to work perfectly with gdb, but now with lldb I'm trying to use the same setup with meson test but even pointing --gdb-path /usr/bin/lldb I'm getting errors like this:

error: unknown option: --quiet
error: unknown option: --args
Use 'lldb --help' for a complete list of options.

My suggestion: Maybe some option like --gdb-args to at least remove unsupported options solves this problem (and even others non-gdb) debuggers to work with meson unit tests.

[tristan957]

A better idea might be to make --debugger and --debugger args arguments, and lose the gdb-specific stuff. cc @eli-schwartz for thoughts.