* _mingw.h (__debugbreak): Add prototype before the inline as it
appears in intrin.h.
* winnt.h: Move the intrin.h include before the __faststorefence
inline. Remove the redundant prototype for _m_prefetchw() which
is already in intrin.h.

git-svn-id: svn+ssh://svn.code.sf.net/p/mingw-w64/code/trunk@4291 4407c894-4637-0410-b4f5-ada5f102cad1