We need to call waitpid until no more waitable children are available.
This is necessary because SIGCHLD signals may coalesce into one when
multiple children terminate almost simultaneously.
Also, switch to EventLoop's asynchronous signal handling mechanism,
which allows more complex operations in the signal handler.
We need to update all button rectangles when the layout changed.
We also need to clear the taskbar button rectangle when we
remove a modal window button, so that WindowServer uses the
parent's taskbar button rectangle for the minimize animation.
With this, System Monitor has "System Monitor" instead of
"SystemMonitor" as tooltip, matching the app's title bar
and menu bar title.
Same for File Manager and Text Editor.
If a window in the taskbar has progress, we'll now draw that progress
in the form of a progress bar behind the window title on the taskbar
button for the window.
.. and make travis run it.
I renamed check-license-headers.sh to check-style.sh and expanded it so
that it now also checks for the presence of "#pragma once" in .h files.
It also checks the presence of a (single) blank line above and below the
"#pragma once" line.
I also added "#pragma once" to all the files that need it: even the ones
we are not check.
I also added/removed blank lines in order to make the script not fail.
I also ran clang-format on the files I modified.
* In some cases, we can first call sigaction()/signal(), then *not* pledge
sigaction.
* In other cases, we pledge sigaction at first, call sigaction()/signal()
second, then pledge again, this time without sigaction.
* In yet other cases, we keep the sigaction pledge. I suppose these could all be
migrated to drop it or not pledge it at all, if somebody is interested in
doing that.
Previously we were wasting the bottom pixel row on darkness. Use the
base button color all the way to the bottom row and offset the top
highlight by one pixel instead.