Windows: use the GUI subsystem, attach to console

This is necessary to start mpv without forcing a console window,
but also breaks console usability. A workaround is to call mpv
from a wrapper process that uses the console subsystem and helps
redirecting the standard streams and WriteConsole output to where
they belong.

waftools/detections/compiler.py

@@ -36,7 +36,7 @@ def __add_mingw_flags__(ctx):
     ctx.env.CFLAGS += ['-DBYTE_ORDER=1234']
     ctx.env.CFLAGS += ['-DLITLE_ENDIAN=1234']
     ctx.env.CFLAGS += ['-DBIG_ENDIAN=4321']
-    ctx.env.LAST_LINKFLAGS += ['-mconsole']
+    ctx.env.LAST_LINKFLAGS += ['-mwindows']
 
 def __add_cygwin_flags__(ctx):
     ctx.env.CFLAGS += ['-mwin32']