Debian package: Add XULRunner 20 compatibility
Debian package: consistently use "touch $@" for stamp files
Debian package: use dh_auto_{build,clean}
Debian package: Don't clean up stamp files manually

This is already done by dh_clean + debhelper compatibility level 7
Debian package: clean up rules file

Remove unnecessary comments and blank lines. Also add some blank lines
to gather related lines together in blocks.
Debian package: Use more debhelper magic

No more manual copying, symlinking or directory creating.
Debian package: Use sed inline edits in combination with dh_install
Debian package: Use variable for common path in debian/rules
Debian package: Bump debhelper compatibility to 9

Remove inclusion of buildflags.mk from debian/rules, no more needed.
Debian package: Switch to a dh style debian/rules
Debian package: clean up changelog entry
Makefile: Only set CFLAGS if not already set
Debian package: Mention changed CFLAGS handling in debian/changelog
hacky temporary solution to http://bugs.conkeror.org/issue410

Use this for meta modifier (e.g. put in init file):
new modifier(function (event) { return event.isMeta || isMeta; },
             function (event) { event.isMeta = true; });

Since event objects are read-only, a global meta-modifier state is
needed. This creates at least 1 new problem: key aliases retain the meta
modifier, i.e. M-c becomes C-M-w when this is defined:
define_key_alias("M-c", "C-w");
another hack to solve the problem created by previous commit c4e3518

Use like this:
new modifier(
  function (event) {
    if (event.faked_by_overlay)
      return false;
    return event.isMeta || isMeta;
  },
  function (event) { event.isMeta = true; });