Draw the FunctionBar within Panel_draw instead of manually throughout
the code.
Add an optional PanelClass function drawFunctionBar, to allow specific
panels to override the default FunctionBar_draw call.
Rework the code on color change, to really change all colors (selection
markers and panel headers).
Closes: #402
Implements the suggestion from https://github.com/htop-dev/htop/issues/399#issuecomment-747861013
Thanks to the refactors from 0bd5c8fb5da and 6393baa74e5, this was really easy
and clean to do.
It maintains the "Tree view always by PID" option in the Settings, which
results in some specific behaviors such as "clicking on the column header to
exit tree view" and "picking a new sort order to exit tree view", for the sake
of the muscle memory of long time htop users. :)
Reasoning:
- implementation was unsound -- broke down when I added a fairly
basic macro definition expanding to a struct initializer in a *.c
file.
- made it way too easy (e.g. via otherwise totally innocuous git
commands) to end up with timestamps such that it always ran
MakeHeader.py but never used its output, leading to overbuild noise
when running what should be a null 'make'.
- but mostly: it's just an awkward way of dealing with C code.
Promote the Arg union to a core data type in Object.c such
that it is visible everywhere (many source files need it),
and correct declarations of several functions that use it.
The Process_sendSignal function is also corrected to have
the expected return type (bool, not void) - an error being
masked by ignoring this not-quite-harmless warning. I've
also added error checking to the kill(2) call here, which
was previously overlooked / missing (?).