Compiling tsearch2 on AIX

I am trying to compile PostgreSQL 8.0.3/tsearch2 contrib module on AIX 5.2 ML 3

gcc version 3.3.2
GNU Make 3.80

bash-2.05b# gmake
gcc -O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wendif-labels
-fno-strict-aliasing -I./snowball -I./ispell -I./wordparser -I.
-I../../src/include -c -o dict_ex.o dict_ex.c
In file included from ../../src/include/c.h:64,
from ../../src/include/postgres.h:48,
from dict_ex.c:9:
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:484:
error: conflicting types for `fgetpos64'
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:310:
error: previous declaration of `fgetpos64'
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:487:
error: conflicting types for `fseeko64'
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:430:
error: previous declaration of `fseeko64'
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:488:
error: conflicting types for `fsetpos64'
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:312:
error: previous declaration of `fsetpos64'
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:489:
error: conflicting types for `ftello64'
/opt/freeware/lib/gcc-lib/powerpc-ibm-aix5.2.0.0/3.3.2/include/stdio.h:431:
error: previous declaration of `ftello64'
gmake: *** [dict_ex.o] Error 1

Can someone please let me know why this is happening?