When building Python in some uncommon platforms (I am looking at you Solaris and AIX) there are some known tests that will fail. Right now, regrtest has the ability to ignore entire tests using the -x option and to receive a filter file using the --matchfile filter.

The problem with the --matchfile option is that it receives a file with patterns to accept and when you want to ignore a couple of tests and subtests, is too cumbersome to lists ALL tests that are not the ones that you want to accept.

The problem with -x is that is not easy to ignore just a subtests that fail and the whole tests needs to be ignored.

So I suggest to add a new command line option similar to --matchfile but the other way around. Another possibility is allowing to reverse the meaning of the matchfile argument, but I find that a bit more confusing.