Update llvm-37 to release instead of svn, remove subversion dependency

[sierkb@…]

LLVM 3.7.1 release has been officially announced on Jan 05 2016, see announcement ​http://lists.llvm.org/pipermail/llvm-announce/2016-January/000066.html, downloadable here: ​http://llvm.org/releases/download.html#3.7.1. It is an official stable release.

Since official stable tarballs are available from the project's website, I guess, there's is no need to use the SVN checkout and therefore no longer need to let this port be dependent on subversion port, since also the official LLVM documentation for
LLVM 3.4.x states on ​http://llvm.org/releases/3.4/docs/GettingStarted.html#software:

Getting Started with the LLVM System
[...]
Requirements
[...]
Software
[...]
SVN >=1.3 Subversion access to LLVM ²
[...]

2. You only need Subversion if you intend to build from the latest LLVM sources. If you’re working from a release distribution, you don’t need Subversion.
   [...]
   

Oddly, this note does not occur in the equivalent documentation for
LLVM 3.5 ​http://llvm.org/releases/3.5.0/docs/GettingStarted.html#software,
LLVM 3.6 ​http://llvm.org/releases/3.6.0/docs/GettingStarted.html#software,
LLVM 3.7 ​http://llvm.org/releases/3.7.0/docs/GettingStarted.html#software.

Nevertheless, MacPorts' llvm-3.5.x port as well as llvm-3.6.x port do NOT depend on subversion port, so I guess, the dependency on subversion in fact really is not needed for officially release tarballs from the project's website. I further guess, this would also work for llvm-3.7.x and stable llvm-3.8.x port (if released officially. Be prepared, it is already tagged and branched as final release in SVN repository, so release tarball and announcement for 3.8 should be published very soon).

I furhermore guess, that the note in LLVM 3.4 documentation concerning the dependency on subversion also still is valid for all LLVM versions >= 3.4, and that the lack of this note in newer documentation might be an inadvertence by the LLVM documentation maintainer. Maybe further investigation needed to clear that. MacPorts' llvm-3.5 and llvm-3.6 port prove, that svn checkout and dependency on subversion port is not needed (when based on release tarball).

What is your opinion?

[jeremyhu (Jeremy Huddleston Sequoia)]

The llvm 3.7 port is using the release tarballs from 3.7.1 and has been for quite some time.

I just forgot to remove the dependency on subversion. r146339