On Windows, an application is either console or gui, it cannot be both.
Scrcpy should be both: it outputs important information to console, but
we still want to be able to ignore the console and launch it without a
visible cmd.exe window.
Therefore, build two binaries:
- scrcpy.exe
- scrcpy-noconsole.exe
Build the Windows binary from mingw on Linux, using the official
prebuilt binaries for ffmpeg, SDL2 and adb.
MSYS2 and all its packaged dll are not necessary anymore.
In practice, proc_show_touches may not be used uninitialized, since it
checks the flag options->show_touches, but the compiler can't know that,
so initialize it to avoid the warning.
Romain Vimont