go: build cgo with clang for devel versions.

Closes #23119.
BuildOptions: detect if building a bottle.
mpfr: remove incorrect gmp comment.
gmp: disable assembly when building bottles.
gmp: add new bottles without assembly.

Closes #23114.
Boost: simplify universal handling and other improvements.

* Use Homebrew standard universal handling.
* Handle whether to build MPI at bootstrap.
  - Also improve parameter construction.
  - Use CPU.is_32_bit? instead of accessing CPU.bits directly.
* Add more caveats:
  - Boost.Log is disabled when building using apple-gcc42 or llvm-gcc.
  - Boost.Context and Boost.Coroutine are only supported on x86_64.
brew-test-bot: cleanup junit file with iconv.
Revert "brew-test-bot: cleanup junit file with iconv."

This reverts commit 5e26584736b310c365d4b9cce99d0dced9a2d309.
ruby-build 20131008

Closes #23127.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
nginx 1.4.3

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
nginx: devel 1.5.6

Closes #23130.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
youyube-dl 2013.10.07

Closes #23129.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
lilypond devel 2.17.28

Closes #23121.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
flowgrind 0.6.1

Closes #22842.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Merge branch 'master' of http://github.com/mxcl/homebrew