Platform: suppress data-to-function-pointer cast warning on MinGW.

src/Magnum/Platform/WindowlessWglApplication.cpp

@@ -122,6 +122,9 @@ WindowlessWglContext::WindowlessWglContext(const Configuration& configuration, G
 
     /* Get pointer to proper context creation function */
     typedef HGLRC(WINAPI*PFNWGLCREATECONTEXTATTRIBSARBPROC)(HDC, HGLRC, const int*);
+    #ifdef CORRADE_TARGET_GCC
+    __extension__ /* http://web.archive.org/web/20160826013457/http://www.mr-edd.co.uk/blog/supressing_gcc_warnings */
+    #endif
     const PFNWGLCREATECONTEXTATTRIBSARBPROC wglCreateContextAttribsARB = reinterpret_cast<PFNWGLCREATECONTEXTATTRIBSARBPROC>( wglGetProcAddress(reinterpret_cast<LPCSTR>("wglCreateContextAttribsARB")));
 
     /* Request debug context if GpuValidation is enabled either via the