Fix compilation with mingw.org headers

-std=c++11 sets __STRICT_ANSI__, and the stdio.h from mingw.org doesn't
declare e.g. _fileno then.

Change-Id: Iaa29e4f2b04bcae73b8706aff1be83913bcf6a52
Reviewed-by: Jonathan Liu <net147@gmail.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

tools/xmlpatterns/xmlpatterns.pro

@@ -12,3 +12,6 @@ HEADERS = main.h                            \
           qapplicationargumentparser.cpp    
 
 load(qt_tool)
+
+# with c++11 / __STRICT_ANSI__ mingw.org stdio.h doesn't declare e.g. _fileno
+win32-g++*: QMAKE_CXXFLAGS_CXX11 = -std=gnu++0x
\ No newline at end of file