d_do_test: make used C++ compiler configurable
allocate a little less than 64kB per chunk to avoid larger allocations due to C runtime overhead
fix issue 10646 - [ICE] when casting dynamic array/static array to class
reference
updated comment regarding chunk size
fix Issue 10642 - Win64: wrong codegen comparing different sized integer arguments
Merge pull request #2351 from rainers/chunk_mem_align

Reduce memory overhead caused by chunk allocation
Merge pull request #2348 from hpohl/10646

fix issue 10646 - [ICE] when casting dynamic array/static array to class reference
Merge pull request #2342 from rainers/test_configure_cc

d_do_test: make used C++ compiler configurable
Merge pull request #2352 from WalterBright/fix10642-2

fix Issue 10642 - Win64: wrong codegen comparing different sized integer...