Optimise closure code (but not GC allocations)
Stiffen up type equality matching in glue
Update to latest gcc snapshot
Clean up and remove some ties with common C types emitted from the frontend.
Merge branch 'master' into gdc-4.9

Conflicts:
	gcc.version
	gcc/d/d-builtins.cc
Merge branch 'gdc-4.9' into gdc-4.8