Building 21.1 or 21.2 with latest gcc snapshots

It is not possible to build either 21.1 or 21.2 on my linux 686 system with the latest egcs/gcc snapshot. I get a core dump running temacs. I tracked this down to the following line in r_alloc_sbrk in src/ralloc.c (line 804 in the current 21.1 sources): return (*real_morecore) (size); with size = 0. I recompiled ralloc.c with -fno-strict-aliasing, and voila! I can build and run an XEmacs. Perhaps someone who understands the aliasing issues better than I do can track this down, he or she cares to. - vin PS. This problem did not appear with gcc-2.95.1 - it's something that has only cropped up with the latest compiler snapshots.