Rename contrib/tools/chkfmt to contrib/tools/chkfmt.sh; refactor:
* Increase the max line length for contrib/**/*.[ch] from 96 to 100.
* Set the max line length for ci_*.sh to 100.
* Use `basename $0` instead of the hard-coded script name.
* Update comments.
Remove contrib/tools/reindent. For automated code formatting, including
indentation, we need a robust solution.
Add an empty line after the hashbang line in all scripts.
Remove the "last changed" version info from comment headers.
(The version control system maintains this information automatically.)
prefixing This adds an API to set optimization options externally,
providing an alternative and general solution for the non-portable
run-time tests used by the ARM Neon code. It also makes those tests
compile and link on Android.
The order of settings vs options in pnglibconf.h is reversed to allow
settings to depend on options and options can now set (or override) the
defaults for settings.
