pmb.helpers.pmaports: glob just once
Fixes #1896 (closed).
- Approximate time taken globbin' before @drebrez's changes: 17.3 seconds
- With @drebrez's changes: 0.13 seconds
- With these changes: 0.02 seconds
I don't think it's worth to make a sophisticated benchmark test - it's obvious that a single glob takes less time than multiple. Also these changes are more about keeping the code nice and clean than improving the performance even further. @drebrez already fixed the main performance bottleneck. (Thanks!)