[Dovecot] libsieve compilation error on AIX 5.3

Dovecot revision: 9186:f70192e7ff3c libsieve revision: 958:e86a81f4bf28 Using IBM c compiler version 8.

Trying to compile libsieve(64 bit mode if it matters):

"sieve-ast.c", line 302.9: 1506-045 (S) Undeclared identifier last. "sieve-ast.c", line 302.9: 1506-045 (S) Undeclared identifier result. "sieve-ast.c", line 320.9: 1506-275 (S) Unexpected text node
encountered. "sieve-ast.c", line 320.9: 1506-045 (S) Undeclared identifier node. "sieve-ast.c", line 324.9: 1506-045 (S) Undeclared identifier last. "sieve-ast.c", line 324.9: 1506-045 (S) Undeclared identifier result. gmake[4]: *** [sieve-ast.lo] Error 1

Thanks, Jonathan