lang/python39: fix build on GCC architectures

Use newer GCC:
/wrkdirs/usr/ports/lang/python39/work/Python-3.9.0/Modules/_zoneinfo.c: In function 'calendarrule_new':
/wrkdirs/usr/ports/lang/python39/work/Python-3.9.0/Modules/_zoneinfo.c:1227: error: #pragma GCC diagnostic not allowed inside functions
/wrkdirs/usr/ports/lang/python39/work/Python-3.9.0/Modules/_zoneinfo.c:1228: error: #pragma GCC diagnostic not allowed inside functions
/wrkdirs/usr/ports/lang/python39/work/Python-3.9.0/Modules/_zoneinfo.c:1229: warning: comparison is always false due to limited range of data type
/wrkdirs/usr/ports/lang/python39/work/Python-3.9.0/Modules/_zoneinfo.c:1230: error: #pragma GCC diagnostic not allowed inside functions