lib: Mark up error names in man pages with .Er

Use .In for header files instead of .Ar Pa and variations.

We have 2005.

match reality

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22280, verified by myself.

Misc. fixes from jmc@openbsd.

Use
.In header.h
instead of
.Fd #include \*[Lt]header.h\*[Gt]
Much easier to read and write, and supported by groff for ages.
Okayed by ross.

Generate <>& symbolically.

Standardize section header.

branches: 1.18.8;
remove the list of signals and xref signal(7) instead

branches: 1.17.4;
Last of the .Os cleanups. .Os is defined in the tmac.doc-common file,
so we shouldn't override it with versions in the manpages. Wheee!

first pass at fixing up capitalization of function names and
arguments; ensure that each is correct with respect to the
implementation, rather than being correct as per english.

fix bad .Xr references

fix mdoc reference

add LIBRARY section to man page

merge lite-2

Minor wording changes, and update the date.

Declare the return type.

sv_mask is an int, not a sigset_t.
Copy some additional wording from sigaction(2).
Various other formatting and wording fixes.

branches: 1.8.2;
xref sig{block,setmask}(3) not sig{block,setmask}(2), and RCSid police.

change sigpause(2) to sigsuspend(2) or sigpause(3), depending
Also try to fix other bad references to sig* man pages.
Fixes pr-2885 from Jonathan Stone
These SEE ALSO sections are still bloody messes (sigh)

eliminate incorrect self-reference.

these are library routines, not syscalls. per jtc's suggestion.

Fix spelling errors.

Use "Er" for argument to -width in the lists in the ERROR sections so that
formatting is consistant.

Add RCS indentifiers.

branches: 1.1.1;
Initial revision