[krbdev.mit.edu #3213]

[Jeffrey Altman via RT]

A patch to gssapiP_generic.h rel_buffer.c, util_buffer.c:

Prepend to all gssapi library allocated gss_buffer_t value fields
a magic 32-bit unsigned value (MIT_KG_MALLOC_MAGIC) for use in
generic_gss_release_buffer() to ensure that we do not call xfree()
on a buffer which was not allocated by the library.  Deallocation
of buffers is not safe except by the instance of the C Run Time
Library used to perform the allocation.

This patch almost certainly does not get the alignment issues correct
but I believe is a reasonable approach.