lang/parrot: unbreak with ICU 64

In file included from src/ops/core_ops.c:72:
In file included from /usr/local/include/unicode/uchar.h:28:
In file included from /usr/local/include/unicode/utypes.h:38:
In file included from /usr/local/include/unicode/umachine.h:46:
In file included from /usr/local/include/unicode/ptypes.h:52:
In file included from /usr/local/include/unicode/platform.h:25:
/usr/local/include/unicode/uvernum.h:123:8: error: 'U_DISABLE_VERSION_SUFFIX' is not defined, evaluates to 0 [-Werror,-Wundef]
#elif !U_DISABLE_VERSION_SUFFIX

^

PR: 236325
Approved by: portmgr blanket