Fix type-punned pointer dereference warning.

Accessing a variable via a pointer of a different type is discouraged
because it makes it much harder for the compiler to perform certain
optimizations.  The compiler warns that "dereferencing type-punned
pointer will break strict-aliasing rules".

Change-Id: I23a030c11dac6b335b96ae90b3d75d250bb7aa99
Merge topic 'type-punned-pointer' into master

ac95ec88 Fix type-punned pointer dereference warning.