The current sed_checked.sh validates REINPLACE_CMD expressions in port Makefiles.
It has a few shortcomings that this diff strives to address:
- the test is blind to whether a REINPLACE_CMD line is completely useless, or partially ineffective - report that because for some machine edits, a broader glob has been common practice
- REINPLACE_CMD may suppress creation of backup files (-i ''), which invalidates this check, so warn about that
- report found data immediately, and again through REWARNFILE.