[Lazarus] Debugger backends configuration

[Zoë Peterson]

What controls what appears in the "Debugger type and path" dropdown in 
the Debugger backend preferences?

I have two macOS systems, one running 10.13 and one 10.14 that have 
different items listed.  The 10.13 one lists fpdebug, GDB, and LLDB 
based ones (6 total) and I've been successfully using "LLDB debugger 
(with fpdebug) (Beta)".  The 10.14 one only lists the GDB based ones in 
the dropdown though.

We have some custom commands in our build scripts, and both FPC and Laz 
are slightly out of date from trunk, (FPC more so right now).  I'm 
building on both systems using identical scripts though, and even tried 
wiping FPC, Lazarus, and their configurations off the system and 
starting from a fresh FPC 3.04a install.  Currently building Lazarus as 
64-bit with the Cocoa widgetset, using Xcode 10.

Where should I look for whatever is going wrong or being excluded?

Thanks!

-- 
Zoë Peterson
Scooter Software