scons: Disable MSVC warnings about inconsistent function annotation.

Somehow, merely including any of the *intrin.h headers causes dozens of
this warnings (when compiling pretty much every source file).  MSVC does
not always complain the same -- so it's possible we're doing something
weird --, but silence these warnings in the meanwhile.

Reviewed-by: Brian Paul <brianp@vmware.com>
1 file changed