I hit a random failure in elf2flt (not elf2flt's fault, I was screwing with

I hit a random failure in elf2flt (not elf2flt's fault, I was screwing with
ELFs and LMAs/VMAs), but the resulting error message was useless:
malloc: Cannot allocate memory

Since I was executing `...-gcc` at the time, where exactly this error message
was coming from was hard to say.  So instead of using malloc() and then doing
a simple 'perror("malloc"); exit(1);' in the elf2flt.c code, it'd be better
for everyone if we used the xmalloc() funcs from libiberty.  We're already
linking elf2flt against libiberty, so there's no extra headers/libs to link
against.

Now the crash looks like:
bfin-uclinux-elf2flt: out of memory allocating 4221960244 bytes after a total of
 135168 bytes
So much nicer! :)

Signed-off-by: Mike Frysinger <vapier@gentoo.org>