[PATCH] fortran/67758 -- Prevent ICE caused by misplaced COMMON

[Steve Kargl]

Patch built and regression tested on x86_64-*-freebsd.
OK to commit?

The patch prevents the dereferencing of a NULL pointer
by jumping out of the cleanup of a list of COMMON blocks.

2015-09-30  Steven G. Kargl  <ka...@gcc.gnu.org>

        * symbol.c (gfc_restore_last_undo_checkpoint): Prevent ICE during
        cleanup of a misplaced COMMON.

2015-09-30  Steven G. Kargl  <ka...@gcc.gnu.org>

        * gfortran.dg/pr67758.f: New test.

-- 
Steve