* flag-set.cocci: perform the transformation only if the second
argument is a constant
* sd-journal/lookup3.c: skip the cocci completely for this file, since
it's not "ours"
* strjoina.cocci: skip the transformation on the "test_strjoina" test,
since it intentionally tests the "incorrect" expression we're trying to
transform (the same thing was already done in strjoin.cocci)
Some transformations generate results we don't want to keep, so
let's disable such transformations for specific files.
Also, disable const-strlen.cocci everywhere, as the STRLEN macro has a
pretty limited scope, so the transformation generates false positives in
most cases.
This way we don't need to repeat the argument twice.
I didn't replace all instances. I think it's better to leave out:
- asserts
- comparisons like x & y == x, which are mathematically equivalent, but
here we aren't checking if flags are set, but if the argument fits in the
flags.
