[PATCH] Add Rust support to source highlighting

[Tom Tromey]

>>>>> "Tom" == Tom Tromey <tom@tromey.com> writes:

Tom> Currently, no release of GNU Source Highlight supports Rust.  However,
Tom> I've checked in a patch to do so there, and I plan to make a new
Tom> release sometime this summer.

Tom> This patch prepares gdb for that by adding support for Rust to the
Tom> source highlighting code.

Tom> Because Source Highlight will throw an exception if the language is
Tom> unrecognized, this also changes gdb to ignore exceptions here.  This
Tom> will cause gdb to fall back to un-highlighted source text.

Tom> Tested with the current and development versions of Source Highlight.

This patch works ok on Fedora 28, but on Fedora 29 it causes gdb to
crash.

I don't think there's anything wrong with the patch, so I guess this is
a Fedora bug somehow.  I will see if I can write a test case and file
it.

Meanwhile I think this patch should not go in :-(

Tom