MFC r300395:

Silence top(1) compiler warnings

The contrib/top code is no longer maintained upstream (last pulled 16 years
ago). The K&R-style followed by the code spews -Wimplicit-int and -Wreturn-type
warnings, amongst others. This silences 131 warnings with as little modification
as possible by adding necessary return types, definitions, headers, and header
guards, and missing header includes.

The 5 warnings that remain are due to undeclared ncurses references. I didn't
include curses.h and term.h because there are several local functions and macros
that conflict with those definitions.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Bump MAX_COLS to 512 to take advantage of wider terminals.

Revert r214857 pursudant to 9.0-RELEASE cycle.

Requested by: jh

Inverse display of top(1)'s table header when running in inactive mode.

MFC after: 2 weeks

Add a -P flag to display per-cpu cpu usage stats.

- Add new 'a' switch and runtime option that allows 'top' to display process
titles extracted from argv vector instead of the real executable names.
This is useful when you want to watch applications that set their status
information via setproctitle(3).

Approved by: alfred
MFC after: 2 weeks

New feature, provide a display that shows the amount of IO processes
are doing. Toggle this mode by hitting "m" or passing the command line
option "-m io" to top(1). This allows one to identify disk bandwidth
hogs much easier.

Apply the FreeBSD-local patches.

Obtained from: The ports collection.

This commit was generated by cvs2svn to compensate for changes in r24139,
which included commits to RCS files with non-trunk default branches.

This is the long-awaited import of top into the base system (actually,
the src/contrib/top part right now). This tools is simply too system-
dependant to maintain it in the ports collection.