Log Message:
On Arch Linux, the XEmacs build breaks in src/gmalloc.c because extern
declarations conflict with system headers.  After patching this file,
the build then hangs at

 ./xemacs -nd -batch -l \ 
/var/obj/pkgsrc/editors/xemacs/work/xemacs-21.4.24/src/../lisp/update-elc.el

with the xemacs process spinning at 100% cpu.

Upstream states that the XEmacs malloc has not been updated in a long
time, and that it is safe to use the system malloc, so that's what
we'll do.