configure.ac: MinGW doesn't have setuid binaries either.

If the target platform isn't in a list of platforms we know don't use a
setuid binary, we try to test if we can chown something to root.

This test possibly won't give the right answer if we are cross-compiling,
which is common for the MinGW target.  This patch adds MinGW to the list
of platforms we know don't use a setuid binary.

Signed-off-by: Ryan Pavlik <rpavlik@iastate.edu>
Reviewed-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Yaakov Selkowitz <yselkowitz@users.sourceforge.net>

configure.ac

@@ -657,6 +657,7 @@ AC_MSG_CHECKING([to see if we can install the Xorg server as root])
 if test "x$SETUID" = "xauto" ; then
 	case $host_os in
 	    cygwin*)		SETUID="no"  ;;
+	    mingw*)		SETUID="no"  ;;
 	    darwin*)		SETUID="no"  ;;
 	    *)
 	   	case $host_cpu in