tcsh consumes much cpu when trying to gdb anything

["Nuno Antunes" <nuno.antunes@xxxxxxxxx>]

how to replicate:

1) set the environment variable SHELL=/bin/tcsh
2) gdb /usr/bin/true
3) (gdb) run

a ktrace of the offending process reveals the following:

[...]
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
 2203 tcsh     CALL  fork
 2203 tcsh     RET   fork RESTART
[...]

This is on a recent HEAD.

I'll try to chase this but any help would be appreciated. :)

Cheers,
Nuno