I see the following on this machine: (OSX 10.3.4, gcc 3.3)
[neilc:/Users/neilc/build-pgsql/contrib]% make -s all
ld: warning multiple definitions of symbol _nextval
pending.o definition of _nextval in section (__TEXT,__text)
../../src/backend/postgres definition of _nextval
ld: warning multiple definitions of symbol _setval
pending.o definition of _setval in section (__TEXT,__text)
../../src/backend/postgres definition of _setval
/Users/neilc/pgsql/contrib/pgcrypto/rijndael.tbl:3: warning:
`pow_tab' defined but not used
/Users/neilc/pgsql/contrib/pgcrypto/rijndael.tbl:22: warning:
`log_tab' defined but not used
/Users/neilc/pgsql/contrib/pgcrypto/rijndael.tbl:41: warning:
`sbx_tab' defined but not used
/Users/neilc/pgsql/contrib/pgcrypto/rijndael.tbl:60: warning:
`isb_tab' defined but not used
-Neil