pngcp: add high resolution timing

If PNG_PNGCP_TIMING_SUPPORTED is defined maximal resolution CPU time logging of
png_read_png and png_write_png is enabled via the --time command line option.
This is not on by default but is enabled by contrib/conftests/pngcp.dfa

Signed-off-by: John Bowler <jbowler@acm.org>
2 files changed