Declare the operator== overload for M128A in the global namespace.

ADL will look this up from the callsite namespace iff it is declared
before the callsite or from the parent namespace of the class type (the
global namespace).

This patch has been tested on MSVS 2015 and clang-3.8.

Change-Id: I00ba74712c9b617b9d81761abed1e14d8f25d8e3
1 file changed