changed date of contrib/oss-fuzz files.

deflate buffer for each row (Bug report by Andrew Church).

    by Mick P., Source Forge Issue #269).

missing parenthesis in contrib/pngminus/pnm2png.c (bug report by Christian
Hesse).

whose names differ only in case; this causes problems with some platforms
(github issue #172).

to stop some Coverity issues (162705, 162706, and 162707).

with "II" or "MM".

to account for the minimum 'deflate' stream.

Make pngtest --strict, --relax, --xfail options imply -m (multiple).

num_exif argument to png_get_eXIf_1() (Github Issue 171).

Moved testing of bad pngs into a separate tests/pngtest-badpngs script
Added the --xfail (expected FAIL) option to pngtest.c. It writes XFAIL
    in the output but PASS for the libpng test.

function (Suggested by Max Stepin).

bytes too small (neglected to account for a partial DEFLATE buffer)

no longer using deprecated cmake LOCATION feature (Clifford Yapp).

does not work (the eXIf chunk data can contain zeroes).