r312452-r312512:

- Use SRCTOP-relative paths to other directories instead of .CURDIR-relative ones

  This simplifies pathing in make/displayed output

- Use .CURDIR:H instead of .CURDIR to simplify pathing in output, etc

Sponsored by:	The FreeBSD Foundation

This both avoids some dependencies on xinstall.host and allows
bootstrapping on older releases to work due to lack of at least 'install -l'
support.

Sponsored by:	EMC / Isilon Storage Division

Since METAMODE has been added, sys.mk loads bsd.mkopt.mk which ends load loading
bsd.own.mk which then defines SHLIBDIR before all the Makefile.inc everywhere.

This makes /lib being populated again.

Reported by:	many

Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.

Still need to add real targets under targets/ to build packages.

Differential Revision:       D2796
Reviewed by: brooks imp

Some users build FreeBSD as non-root in Perforce workspaces.  By default,
Perforce sets files read-only unless they're explicitly being edited.
As a result, the -f argument must be used to cp in order to override the
read-only flag when copying source files to object directories.  Bare use of
'cp' should be avoided in the future.

Update all current users of 'cp' in the src tree.

Reviewed by:	emaste
MFC after:	1 week
Sponsored by:	Spectra Logic