Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r258658:

Fix a segfault / internal compiler error.

Among other causes, when gcc throws a warning before parsing any tokens,
the cur_token pointer is at the beginning of malloc'd memory.
Dereferencing cur_token[-1] can cause a segfault.

Code taken from OpenBSD
http://www.openbsd.org/cgi-bin/cvsweb/src/gnu/gcc/libcpp/errors.c
which was a more complete fix than the one I originally coded.

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

This commit was generated by cvs2svn to compensate for changes in r169695,
which included commits to RCS files with non-trunk default branches.

GCC 4.2.0 release miscellaneous support libraries.