Merge branch 'rj/cygwin-has-dev-tty'

Cygwin does have /dev/tty support that is needed by things like
single-key input mode.

* rj/cygwin-has-dev-tty:
  config.mak.uname: add HAVE_DEV_TTY to cygwin config section

Author: gitster

config.mak.uname

@@ -248,6 +248,7 @@ ifeq ($(uname_O),Cygwin)
         else
 		NO_REGEX = UnfortunatelyYes
         endif
+	HAVE_DEV_TTY = YesPlease
 	HAVE_ALLOCA_H = YesPlease
 	NEEDS_LIBICONV = YesPlease
 	NO_FAST_WORKING_DIRECTORY = UnfortunatelyYes