Building Python 3.0.1 with xlc on AIX 5.3, The following compiler 
errros come up:
/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 141.25: 1506-045 
(S) Undeclared identifier FFI_LINUX_SOFT_FLOAT.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 601.19: 1506-045 
(S) Undeclared identifier FFI_LINUX_SOFT_FLOAT.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 604.19: 1506-045 
(S) Undeclared identifier FFI_LINUX64.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 668.23: 1506-045 
(S) Undeclared identifier FFI_SYSV.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 902.10: 1506-045 
(S) Undeclared identifier FFI_SYSV.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 902.10: 1506-051 
(S) Case expression must be a valid integral constant.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 903.10: 1506-045 
(S) Undeclared identifier FFI_GCC_SYSV.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 903.10: 1506-051 
(S) Case expression must be a valid integral constant.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 904.10: 1506-045 
(S) Undeclared identifier FFI_LINUX.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 904.10: 1506-051 
(S) Case expression must be a valid integral constant.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 905.10: 1506-045 
(S) Undeclared identifier FFI_LINUX_SOFT_FLOAT.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 905.10: 1506-051 
(S) Case expression must be a valid integral constant.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 1027.26: 1506-045 
(S) Undeclared identifier FFI_SYSV.
"/home11/eeshel/dev/python/Python-
3.0.1/Modules/_ctypes/libffi/src/powerpc/ffi.c", line 1152.27: 1506-045 
(S) Undeclared identifier FFI_LINUX_SOFT_FLOAT.

Configuration command was:
configure --prefix=/home/eeshel/bin/python/python-3.0.1 --exec-
prefix=/home/eeshel/bin/python/python-3.0.1/ibm --with-
gcc="/bb/util/version10-022009/usr/vacpp/bin/xlc_r -Wl,-G" --with-
cxx="/bb/util/version10-022009/usr/vacpp/bin/xlc_r -Wl,-G" --disable-
ipv6 --disable-shared --with-threads