Gcc compilation problem on AIX 6.1

Hi,
I have to compile a program on my server, runs on AIX 6.1. On my test server the compilation is ok (AIX 6.1); but when I try it on production server, I have this

gcc prog.c -o prog_out
In file included from resmon.c:111:
/usr/include/unistd.h:924: error: expected ')' before '[' token
/usr/include/unistd.h:925: error: expected declaration specifiers or '...' before 'rid_t'

I noticed that the gcc version is the same (4.2.0) but not the target.
Production:

gcc -v
Using built-in specs.
Target: powerpc-ibm-aix5.3.0.0
Configured with: ../configure --with-as=/usr/bin/as --with-ld=/usr/bin/ld --enable-languages=c,c++,java --prefix=/opt/freeware --enable-threads --enable-version-specific-runtime-libs --host=powerpc-ibm-aix5.3.0.0 --target=powerpc-ibm-aix5.3.0.0 --build=powerpc-ibm-aix5.3.0.0 --disable-libjava-multilib
Thread model: aix
gcc version 4.2.0

Test:

gcc -v
Using built-in specs.
Target: powerpc-ibm-aix6.1.0.0
Configured with: ../configure --with-as=/usr/bin/as --with-ld=/usr/bin/ld --enable-languages=c,c++,java --prefix=/opt/freeware --enable-threads --enable-version-specific-runtime-libs --host=powerpc-ibm-aix6.1.0.0 --target=powerpc-ibm-aix6.1.0.0 --build=powerpc-ibm-aix6.1.0.0 --disable-libjava-multilib
Thread model: aix
gcc version 4.2.0

Is it possible to be the target version that cause this problem?
If yes can I simply update it? (rpm -Uvh gcc-4.2.0-3.aix6.1.ppc.rpm)

New to AIX!!

Thanks for help

Generally, dev is the same revision as prod, and you ship objects, not source, to prod. In some milieu, tools like compilers in prod are a security concern.