Debugging without using -wrapper

[davidmalcolm]

The debugging page mentions -wrapper, but maybe we should document the other way of debugging gdb: passing in -v, and then looking for the line that invokes cc1 (or whatever), as per https://gcc-newbies-guide.readthedocs.io/en/latest/binaries-and-processes.html

Once you've got that command line (usually long and complicated), you can run it under gdb directly via:

gdb --args COMMAND LINE ARGS GO HERE