fix several build warnings

This fixes all but one of the warnings documented in issue #2685. The
sole remaining warning is from the

    string split '' abc

example in doc_src/string.txt. That example results in the man page
displaying

    string split {} abc

I leave it to someone else to fix that problem (I'll open an issue
specifically for it since it took some effort to track down the source
of the warning).

Resolves issue #2685.

0 files changed, 0 insertions, 0 deletions