Remove 'make update'.

[jhb]

Summary

In the CVS days this used be a wrapper around either CVS or CVSup and
used to support updating src, doc, and ports checkouts. With the move
to subversion this only supported updating src and was itself a
wrapper around 'svn update'. With Git, users are probably better off
using appropriate Git commands directly to update without needing an
explicit make target as a wrapper.

[bcr]

OK from manpages.

[imp]

Does this need companion commits to the FreeBSD handbook or related docs?

[imp]

books/handbook/mirrors/_index.adoc:# make update SVN_UPDATE=yes

[jhb]

In D30736#690926, @imp wrote:

books/handbook/mirrors/_index.adoc:# make update SVN_UPDATE=yes

Humm, yes, likely so.

[jhb]

In D30736#690927, @jhb wrote:

In D30736#690926, @imp wrote:

books/handbook/mirrors/_index.adoc:# make update SVN_UPDATE=yes

Humm, yes, likely so.

Humm, actually, this document needs a severe gutting as it has lots of no-longer-relevant subversion bits.

[jhb]

So there is already sign-posting for the handbook bits that svn isn't used anymore, and I think the reference to 'make update' can be axed from the handbook when this section is axed from the handbook when 12.x is EOL. 'make update' is still relevant on the old stable branches where svn is still relevant.