chg: always wait for pager Previously, when runcommand raises, chg aborts with, and does not wait for pager. The call stack is like: hgc_runcommand -> handleresponse -> readchannel -> debugmsg("failed to read channel") -> exit(255) That means, chg returns to the shell, then both the pager and the shell will read from the terminal at the same time, causing problems. This patch fixes that by using "atexit" to register the pager cleanup function so chg will always wait for pager even if runcommand raises.