Usually r->nused < r->nalloc and the read is in bounds.
But it could in theory be right on the line and reading
past the end of the allocation.

Make it safe but preserve as much of the old semantics
as possible. This use of rterm appears to be only for
optimization purposes so the result does not matter
for correctness.

Remote whitespace at the ends of lines.
Remove blank lines from the ends of files.
Change modes on source files so that they
are not executable.

Signed-off-by: Dan Cross <cross@gajendra.net>