Change -Wundef to -Wundef{,-in-if,-noop}
Fix undef test
Allow flex-arrays through struct/union member completness check
Removed unused test scripts + moved comma.c to subdir
Added run_tests - handles output and ignoring expected failures
run_tests and test.pl subsume wrapper script logic
Test fixes

Also added for-loop redecl test
Use die2() in test.pl instead of warn+exit
Test run update