Demangling in backtraces

[Eli Zaretskii]

I have built a C program linked against libgccjit.  When it crashes,
the backtrace shows mangled names, like this:

 #0  0x70f5ac3e in libgccjit-0!_Z17gimple_build_callP9tree_nodejz ()
    from D:\usr\bin\libgccjit-0.dll
 #1  0x7190fa7b in libgccjit-0!_ZN19evrp_range_analyzer5leaveEP15basic_block_def
 () from D:\usr\bin\libgccjit-0.dll
 #2  0x71910eef in libgccjit-0!_Z36stmt_uses_0_or_null_in_undefined_wayP6gimple
     () from D:\usr\bin\libgccjit-0.dll
 #3  0x710fba2c in libgccjit-0!_Z16execute_one_passP8opt_pass ()
    from D:\usr\bin\libgccjit-0.dll

(This is because libgccjit is written in C++, and because the DLL is
stripped.)

How can I cause GDB to demangle the function names when showing the
backtrace in this case?  I tried setting language to c++, but that
didn't help.

TIA