iOS: Added support for iOS 8 LaunchScreen NIBs.

iOS 8 introduces LaunchScreen NIBs which use autolayout to handle all devices and orientations with a single NIB instead of multiple launch images. This is also the only way to get the App Store badge "Optimized for iPhone 6 and iPhone 6 Plus". So if the application is running on iOS 8 or greater AND has specified a LaunchScreen in their Info.plist, this patch will use the NIB as the launch screen. Otherwise, the code falls back to the legacy code path.

Note: Upon audit of the legacy path, it appears that it does not properly handle the UILaunchImages Info.plist convention. I've added comments inline to the code about this. However, in about a year from now, nobody is going to care about this path since everybody should be using LaunchScreen NIBs.
Fixed bug 2411 - Even if built with --enable-clock_gettime, SDL2 still calls gettimeofday()

Ben Swick

Makes SDL_syscond.c and SDL_syssem.c use clock_gettime(CLOCK_REALTIME) when HAVE_CLOCK_GETTIME is defined.
Fixed bug 2676 - xdnd_version check issue in case ClientMessage

Nitz

I added xdnd_version check to XdndPosition case also
under DEBUG_XEVENTS macro.
by this we can get the action requested by user.

I analysed further and found out that removing xdnd_version check at XdndDrop case is a bad idea because
in XConvertSelection API timestamp should be passed if(xdnd_version >= 1)
otherwise CurrentTime should be passed
So xdnd_version check is important at XdndDrop case

I made xdnd_version as a static so that it can store the version in other cases also.
Fixed bug 2786 - "UCS-2-INTERNAL" iconv encoding is not supported everywhere, use UTF-16LE instead

Jonas Kulla

src/main/windows/SDL_windows_main.c:137:
cmdline = SDL_iconv_string("UTF-8", "UCS-2-INTERNAL", (char *)(text), (SDL_wcslen(text)+1)*sizeof(WCHAR));

I'm trying to compile an SDL2 application for windows using the mingw-w64 32bit toolchain provided by my distro (Fedora 19). However, even the simplest test program that does nothing at all fails to startup with a "Fatal error - out of memory" message because the mingw iconv library provided by my distro does not support the "UCS-2-INTERNAL" encoding and the conversion returns null.

From my little bit of research, it turns out that even though this encoding is supported by the external GNU libiconv library, some glibc versions (?) don't support it with their internal iconv routines, and will instead provide the native endian encoding when "UCS-2" is specified.

Nonetheless, I wonder why the native endianness is considered in the first place when Windows doesn't even run on any big endian archs (to my knowledge). And true enough, 'WIN_StringToUTF8' from core/windows/SDL_windows.h is used everywhere else in the windows backend, which is just a macro to iconv with "UTF-16LE" as source. Therefore it would IMO make sense to use this macro here as well, which would solve my problem (patch attached).