Problem building gdb on AIX 4.3

[Bridges Production Bridges Maintenance]

Hello, I am having a problem building gdb on AIX 4.3.  I was able
to get egcs-1.1 to build, though I had to use the
"configure --disable-multilib" feature to get around a problem
building the libstdc++ library.

Anyway, when I try to build gdb, it complains as follows:

make[1]: Entering directory `/bridges/builds/gdb/gdb-4.17/mmalloc'
gcc -c -g -O2 -DHAVE_VALLOC=1 -DHAVE_GETPAGESIZE=1 -DHAVE_LIMITS_H=1 -DHAVE_STDDEF_H=1  -I. -I./../include ./mm.c
In file included from ./mm.c:37:
sbrk-sup.c:27: conflicting types for `sbrk'
/bridges/gnu/lib/gcc-lib/powerpc-ibm-aix4.3.1.0/egcs-2.91.57/include/unistd.h:573: previous declaration of `sbrk'
make[1]: *** [mm.o] Error 1
make[1]: Leaving directory `/bridges/builds/gdb/gdb-4.17/mmalloc'
make: *** [all-mmalloc] Error 2

So apparantly there is a problem compiling mmalloc/mm.c

Any ideas of how to correct or workaround this problem would be
greatly appreciated.  Please send any response to bcameron@tuc.com
since I am not on the mailing list.  Thanks!

Brian