w32: QEMU applications with SDL are always GUI applications

Since commit 1d14ffa9 (in 2005),
QEMU applications on W32 don't use the default SDL compiler flags:

Instead of a GUI application, a console application is created.

This has disadvantages (there is always an empty console window) and
no obvious reason, so this patch removes the strange flag modification.

The SDL GUI applications still can be run from a console window
and even send stdout and stderr to that console by setting environment
variable SDL_STDIO_REDIRECT=no.
Signed-off-by: NStefan Weil <sw@weilnetz.de>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

configure

@@ -1523,9 +1523,6 @@ EOF
   if compile_prog "$sdl_cflags" "$sdl_libs" ; then
     sdl_libs="$sdl_libs -lX11"
   fi
-  if test "$mingw32" = "yes" ; then
-    sdl_libs="`echo $sdl_libs | sed s/-mwindows//g` -mconsole"
-  fi
   libs_softmmu="$sdl_libs $libs_softmmu"
 fi