The rationale is that you have a packed format in form
<greyscale sample> <alpha sample> <greyscale sample> <alpha sample>
and shortening greyscale to 'G' might make one thing about Greenscale instead.
An alias pixel format and color space name are provided for compatibility.
Otherwise during scaling it will try to interpret input in the wrong way and
that leads to the test results disagreeing on different platforms and with
different optimizations.
Signed-off-by: Diego Biurrun <diego@biurrun.de>
