faust, faust-devel, faustlive-devel: update to 2.5.23 and latest git

[agraef]

This updates faust to 2.5.23 (latest stable release) and faust-devel / faustlive-devel to the latest from the upstream git repositories (https://github.com/grame-cncm) as of today. I also updated the LLVM dependencies to LLVM 6.0 (faust) and LLVM 7.0 (faust-devel, faustlive-devel) so that the ports will hopefully continue to work on Mojave (cf. https://trac.macports.org/ticket/57287). Tested on Sierra (ran it on a few of my own examples, works fine for me).

Test system:
macOS 10.12.6 16G1510
Xcode 9.2 9C40b

[macportsbot]

Notifying maintainers:
@ryandesign for port faust-devel, faust, faustlive-devel.

[macportsbot]

Travis Build #4137 Errored.

Lint results

--->  Verifying Portfile for faust-devel
--->  0 errors and 0 warnings found.
--->  Verifying Portfile for faust
--->  0 errors and 0 warnings found.
--->  Verifying Portfile for faustlive-devel
--->  0 errors and 0 warnings found.

Port faust-devel's dependencies fail on xcode7.3. Log

The build timed out.

[pmetzger]

LGTM. I'll merge it. Thanks, @agraef!