Update the machine-generated configure code.

Fix build on Windows targets without dxgi.h, like MingW32.

Remove code that found its way back into the diff

Fix software rendering in the mir backend. The window assumed hardware buffer, which caused testdrawchessboard to fail to mmap a buffer.

WinRT: suppressed an unused param warning when building for Windows Phone 8.1

WinRT: preliminary support for building against the Windows Phone 8.1 SDK This is a step towards supporting "Universal" Windows apps, when building for Windows Phone. SDL can now build against the Windows Phone 8.1 SDK, and apps linked to it can run, however further work and testing is required as some previously Phone-only code appears to no longer be applicable for Windows Phone 8.1. The Windows 8.1 code paths does seem to be preferable, but should probably be tested and updated on a finer-grained basis. If in doubt, use the Windows Phone 8.0 projects for now, as located in VisualC-WinRT/WinPhone80_VS2012/ TODO: - look at any Windows Phone specific code paths in SDL, and see if Phone 8.1 should use the Windows Phone code path(s), or the Windows 8.x or 8.1 paths

Fixed a linker error when building SDL/WinRT The Win32 APIs, VerifyVersionInfoW and VerSetConditionMask, are not currently available for use in WinRT apps. This change primarily #if[n]defs-out some calls to them.

WinRT: added project files for Windows 8.1 + MSVC 2013 This commit also includes some base-level support for Universal apps. TODO: - add support for Windows Phone 8.1 - add support for satellite libs: SDL_image, SDL_ttf, and SDL_mixer

Removed comma at end of enum in a public header, to make -Wpedantic happy.

Set the tag type in libtool invocations Setting the tag type will let libtool work even when it cannot infer the type of the code being built. One way libtool may fail to infer the tag type is if one uses a mock compiler (such as for static analysis).