Detect debug-file-directory for gdb installed by Nix

[tesuji]

Type of feature request

Debuginfo

Misc

No response

Summary Description

pwndbg detects or has the default of debug-file-directory as /nix/store/k51rfv38p65jbhw906vpl85yg1vd7xqn-gdb-15.2/lib/debug:/usr/lib/debug. Meanwhile gef and raw gdb has the default /nix/store/k51rfv38p65jbhw906vpl85yg1vd7xqn-gdb-15.2/lib/debug.

Implementation idea/suggestion

It might be possible to detect if /usr/lib/debug exist. If yes, then add that path with set debug-file-directory <path> command.

Existing alternatives?

N/A.

Additional information

gef➤  help set debug-file-directory
Set the directories where separate debug symbols are searched for.
Separate debug symbols are first searched for in the same
directory as the binary, then in the `.debug' subdirectory,
and lastly at the path of the directory of the binary with
each global debug-file-directory component prepended.
gef➤  version
GEF: (Standalone)
Blob Hash(/home/hacker/.gef.py): 3cf857c4a9a80e4cf0d1a1345cd672b9631341e0
SHA256(/home/hacker/.gef.py): af072d7fe7e66a08dcf0a78f8c5d39ed04fef670837d7c5384e288ea656bd239
GDB: 15.2
GDB-Python: 3.12