clang/llvm 6.0.0

[Jonathan Perkin <jperkin%joyent.com@localhost>]

Hi,

I've recently been working on packages for clang, llvm, compiler-rt,
libcxx, and libcxxabi version 6.0.0 (pre-release).  These are prefixed
under $PREFIX/llvm6 and default to using compiler-rt and libcxx (i.e.
no GCC required).

The branch is here:

  https://github.com/NetBSD/pkgsrc/compare/trunk...joyent:joyent/dev/clang

and is now able to over 13,500 packages on SmartOS and increasing:

  http://us-east.manta.joyent.com/pkgsrc/public/reports/trunk/x86_64/20180115.2101/meta/report.html

I'd be interested in feedback on implementing things this way and if
anyone else is interested.

Still to do:

 * Proper runtime dependency handling for libcxx/libcxxabi.

 * Something like USE_PKGSRC_CLANG.  I'm currently using a
   bootstrapped prefix to then build the report above but that means
   dependencies on the bootstrap prefix which is no no no.

 * Update to 6.0.0 when released.

Cheers,

-- 
Jonathan Perkin  -  Joyent, Inc.  -  www.joyent.com