Recent versions of MinGW include strsafe.h in dshow.h. strsafe.h undefines all non-safe string functions, including vsprintf and others, to prevent their usage. This causes QString and others to fail. Defining NO_DSHOW_STRSAFE before including dshow.h prevents this behaviour. Change-Id: I012fecbabc5c11900486c1dfdc970a00613ef6f7 Reviewed-by: Michael Goddard <michael.goddard@nokia.com>