citra: Remove GLFW, Add SDL2
FindSDL2: Do not CACHE SDL2_* variables if library is not found
EmuWindow_SDL2: Set minimal client area at initialisation time
EmuWindow_SDL2: Corrections
EmuWindow_SDL2: Fix no decorations on startup on OS X
cmake: windows_copy_files
Using this variable is problematic is the user has several versions of
Qt installed on their system. There is no way to know ahead of time if
the Qt version pointed to by QTDIR matches the toolchain that is being
targeted.
The Qt installation path can still be easily specified if it's not found
by CMake by setting the Qt5_DIR cache variable after the initial
configuration run, so this shouldn't present an usability issue.
No idea why these spaces are only added on recent revisions of Citra
(older revisions did not have this problem).
Let's just remove the spaces then in Powershell.
The submodule update was doing a full clone. Also increase clone depth a
bit, since it can apparently cause issues checking out the source if
there are too many concurrent PRs trying to build (causing the commit
for the build to not be the top one on the repository anymore).