[PATCH] SDL 2.0.4 devel version breaks Windows build

[historic_bruno]

I tested the latest SDL 2.0.4 dev copy from Hg, and there are various Windows build errors related to the main() function. For one thing, we no longer need to define a wmain() function to convert cl arguments to UTF-8, SDL2 does that. Then, the test suite is broken:

1>------ Build started: Project: test, Configuration: Release Win32 ------
1>  test_root.cpp
1>SDL2main.lib(SDL_windows_main.obj) : error LNK2005: _main already defined in test_root.obj
1>     Creating library ..\..\..\binaries\system\test.lib and object ..\..\..\binaries\system\test.exp
1>SDL2main.lib(SDL_windows_main.obj) : error LNK2019: unresolved external symbol _SDL_main referenced in function _main_utf8
1>..\..\..\binaries\system\test.exe : fatal error LNK1120: 1 unresolved externals

I was able to fix this by manually adding #include "lib/external_libraries/libsdl.h" to test_root.cpp, but I don't know how that file is generated or if this might break older SDL versions.

[historic_bruno]

leper pointed me in the right direction for the tests error, I needed to add an include in premake4.lua. The new patch has a little more cleanup for wseh.cpp.

[leper]

I guess we could also remove the MAIN_STARTUP define now (I really think we should just rip ICC related code out since it hasn't been tested in years and likely is broken, but that would be another ticket). Apart from that the patch looks good.

[Itms]

We should get that in ASAP if we want to avoid pushing it to A20.

[historic_bruno]

Note this isn't needed unless we update to SDL 2.0.4 (currently RC), so we can push it to A20 if that doesn't happen.

[leper]

SDL 2.0.4 was released: ​http://lists.libsdl.org/pipermail/sdl-libsdl.org/2016-January/097625.html.

[ben]

In 17658:

Updates precompiled win32 SDL libs to 2.0.4 from libsdl.org.
Fixes windows build with SDL 2.0.4, fixes #3138, #3225

[elexis]

r17658 introduced a bug for hotkeys, see #3870.

[Vladislav Belov]

In 27764:

Fixes linking failure solution introduced in rP17658 for SDL dependency.

Refs #3138

Accepted By: Itms

Differential Revision: ​https://code.wildfiregames.com/D5065