Separate Xcode and CLT doctor checks by OS X version

Closes #29206.
wavpack 4.70.0
youtube-dl 2014.05.05

Closes #29194.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
youtube-dl: update 2014.05.05 bottle.
Add head for libebml
Add head for libmatroska

Closes #29174.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Scrub out --sysroot
Move mpio and msgpack-rpc to boneyard

mpio does not compile with clang or C++11
msgpack-rcp requires mpio
objc-codegenutils 1.0

Closes #28784.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
document FormulaConflict
inline this method
phantomjs: general tweaks and cleanup.
download_strategy: fix Git repo updating.

Git repositories should always be updated when the ref is a branch.
They should be also updated if no ref was specified or if the ref isn’t
present. This stops the repo being updated if we’re building a specific
revision and it is present. Additionally, this stops the update barfing
on repositories where we’re using a revision and there is no upstream
`master` branch.

Closes #29218.
goaccess 0.7.1

Closes #29223.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
bsdconv 11.3.1

Closes #29222.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
sbt --devel 0.13.5-RC2

Closes #29220.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
sysdig 0.1.82

Closes #29217.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
lilypond devel 2.19.6

Closes #29216.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
jython devel 2.7-b2

Closes #29221.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Future-proof this conditional