MFC r326527:

Only skip looking for manpages if both man directory and cat directory
are not existing.

This allows man(1) to read catpages when no man directories are available at all

PR: 223559
Reported by: wosch

MFC r326526:

In case man(1) found a catpage to display skip looking ".so" which is manpage
only.

In case we are trying to read a catpage, the manpage variable is not defined.
It results in the "cattool" having no arguments.

In case the catpage is compressed, the cattool used is "zcat" which dies if the
standard input is a terminal, meaning the function calling it is exiting as if
there were no ".so"
In case the catpage is uncompressed, the cattool used is "zcat -f" which waits
reading standard input, making the man(1) command hang.

PR: 223560
Reported by: wosch

Revert r278650. Definite layer 8 bug.

Submitted by: dhw and Thomas Mueller <tmueller@sysgo.com>

MFC 272315 272757 274091 274902

r272315
Explicitly return None for negative event indices. Prior to this,
eventat(-1) would return the next-to-last event causing the back button
to cycle back to the end of an event source instead of stopping at the
start.

r272757
Add schedgraph traces for callout handlers. Specifically, a callwheel logs
a running event each time it executes a callout function. The event
includes the function pointer, argument, and whether or not it was run from
hardware interrupt context. The callwheel is marked idle when each handler
completes. This effectively logs the duration of each callout routine in
the graph.

r274091
Bind Ctrl-Q as a global hotkey to exit. Bind Ctrl-W as a hotkey to close
dialogs.

r274902
Add a new thread state "spinning" to schedgraph and add tracepoints at the
start and stop of spinning waits in lock primitives.

Reviewed by: jhb

Revert r278650. Definite layer 8 bug.

Submitted by: dhw and Thomas Mueller <tmueller@sysgo.com>

MFC 272315 272757 274091 274902

r272315
Explicitly return None for negative event indices. Prior to this,
eventat(-1) would return the next-to-last event causing the back button
to cycle back to the end of an event source instead of stopping at the
start.

r272757
Add schedgraph traces for callout handlers. Specifically, a callwheel logs
a running event each time it executes a callout function. The event
includes the function pointer, argument, and whether or not it was run from
hardware interrupt context. The callwheel is marked idle when each handler
completes. This effectively logs the duration of each callout routine in
the graph.

r274091
Bind Ctrl-Q as a global hotkey to exit. Bind Ctrl-W as a hotkey to close
dialogs.

r274902
Add a new thread state "spinning" to schedgraph and add tracepoints at the
start and stop of spinning waits in lock primitives.

Reviewed by: jhb