I updated my patches to OpenCASCADE 6.2. As usual you need a Linux install first from which you can copy.
I came across 2 special problems:
In the file Standard_ErrorHandler.cxx I had to use a C type cast:
The return value is a pointer to a struct so casting might or might not be dangerous. So far I did not try multithreading.
MMGT_OPT is disabled for __APPLE__ in Standard.cxx. I reenabled it and it seems that mmap()ed memory management is working.