Previously, three similar callback fuctions were used in console
code. This patch unifies these functions to ease maintenance cost.
Fixes: 8aad3a7edeb2 ("Cygwin: console: Fix a problem that minor ID is incorrect in ConEmu.")
Suggested-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>