- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

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

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

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

Build lib/ with WARNS=6 by default.

Similar to libexec/, do the same with lib/. Make WARNS=6 the norm and
lower it when needed.

I'm setting WARNS?=0 for secure/. It seems secure/ includes the
Makefile.inc provided by lib/. I'm not going to touch that directory.
Most of the code there is contributed anyway.

- style.Makefile(9) fix
- first line is $FreeBSD$
- Reorder special variables: DPADD, LPADD, CFLAGS
- Use = instead of += for variables that are initially empty
- Use space instead of tab after :
- Use one tab after =
- Use .SUFFIXES for section 3 manual page which simplifies Makefile a lot
- Use SHAREDIR instead of /usr/share
- Remove SRCDIR in INCS since we set .PATH properly
- Use plural in variable name when it stands for more that one source file

Reviewed by: ru
Approved by: delphij (mentor)

Introduce new ncurses build glues which are part of ncurses 5.6 update.

Approved by: delphij
Inspired by: DragonFly's and lib/bind