This way the process we get by calling rust-{gdb,lldb} is an actual
{gdb,lldb} instance and not (perhaps surprisingly) a script waiting for
the debugger process to finish. Thus, sending a SIGINT to the spawned
process stops execution of the child, for example.
Instead of hard-coding the command to run, using the environment
variable `GDB_CMD` (that defaults to `gdb`) allows using a different
debugger than the default `gdb` executable.
This gives the possibility to use `cgdb` as the debugger, which provides
a nicer user interface. Note that one has to use `GDB_CMD="cgdb --"` to
use cgdb (note the trailing `--`) to let cgdb pass the proper arguments
to `gdb`.
Jeremy Fitzhardinge
Mark Rousskov
ftilde
Benjamin Lamowski
Nicolas Bigaouette
Michael Woerister