D803: extdiff: use pager

[yuja (Yuya Nishihara)]

yuja requested changes to this revision.
yuja added a comment.
This revision now requires changes to proceed.


  Pager should be disabled at least for GUI tools. Otherwise `hg gui-diff &` would
  be suspended by signal. Perhaps curses-based tools would have a similar problem.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D803

To: quark, #hg-reviewers, yuja
Cc: yuja, indygreg, mercurial-devel