Blender Git Loki

Windows: Use TBBMalloc for GMP

TBBmalloc_proxy already takes care of any allocations
being done from MSVC compiled code, some of the dependencies
like GMP cannot be build with MSVC and we have to use
mingw to build them. mingw however links against the older
msvcrt.dll for its allocation needs, which TBBMallocProxy
does not hook.

GMP has an option to supply your own allocation functions
so we can still manually redirect them to TBBMalloc.

In a test-file with a boolean geometry node, this patch
uses 32s effective CPU time compared to 52s before.

Differential Revision: https://developer.blender.org/D11435

Reviewed by Campbell Barton, Ray Molenkamp