When deciding whether or not to turn on automatic color support, git_config_colorbool checks whether stdout is a tty. However, because we run a pager, if stdout is not a tty, we must check whether it is because we started the pager. This used to be done by checking the pager_in_use variable.
This variable was set only when the git program being run started the pager; there was no way for an external program running git indicate that it had already started a pager. This patch allows a program to set GIT_PAGER_IN_USE to a true value to indicate that even though stdout is not a tty, it is because a pager is being used.
Signed-off-by: Jeff King <firstname.lastname@example.org> Signed-off-by: Junio C Hamano <email@example.com>