Blender Git Loki

Fix for scons + mingw64 warning flags fix

So, it turns out my changes here the other day were a bit too over-eager:
-Wdeclaration-after-statement and -Wstrict-prototypes only applied to C code
and not C++ (which that set of flags was getting included for too).

However, -Wno-char-subscripts is fine where it is now, so I've left it in place