Description:

rendercheck is a program to test a Render extension implementation
against separate calculations of expected output.

Tests currently include:
- Destination coordinates correctness
- Source coordinates correctness
- Transformed (FilterNearest) source coordinates correctness.
- Composite with and without mask (with/without component alpha), with 1x1
repeating Pictures and 10x10 Pictures.

Unfortunately, there are currently no command-line arguments to
control its execution. Options, such as verbosity or number of
iterations to encourage pixmap migration, are controlled only in
source.