[Bf-committers] Change of MinGW64 compiler

[Antony Riakiotakis]

There have been a few issues with the new MinGW compiler unfortunately, one
is crashes with missing or packed images (which only happens on scons) and
we have another bug possibly deadlock-related in the tracker. Unfortunately
with me being in GSOC and the insane amount of time it takes to compile
blender in MinGW, especially with scons, I probably won't be able to see to
these bugs soon :/. If we can't resolve these issues we will probably have
to revert to the previous compiler. It might have not supported openmp but
at least it worked as expeceted elsewhere. Still, I hope to resolve the
above issues.