Allow conflicts_with to accept multiple formula names

Closes #22202.
De-duplicate conflicts for mysql and friends
Add reasons for pdf2image, poppler, and xpdf conflicts
superenv: fix no-op system path filtering
cairo 1.12.16
Remove default values from ENV.{cc,cxx}

Closes #22138.
mosh: --enable-completion

Closes #22203.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
universal_archs returns ArchitectureListExtension

Closes #22210.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
geoserver 2.3.5

http://blog.geoserver.org/2013/08/18/geoserver-2-3-5-released/

Closes #22200.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
openvpn: fix compilation on <= :leopard

Fixes mistydemeo/tigerbrew#112.
mongodb: build from source.

Closes #22149.
mongodb: add bottles.
boost: enable bottles, print Python bottle caveat.

Closes #21824.
terminal-notifier 1.5.1

Closes #22215.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
Add --cc= syntax for selecting compilers
Unify compiler selection logic

This unifies the logic for selecting a compiler between superenv and
stdenv. A variation of superenv's `determine_cc`, which now returns a
symbol, has been moved into the shared ENV extension. Stdenv uses the
result of this directly (as it's always used symbols), while superenv
translates that back into a compiler string.

This also has the effect of disabling HOMEBREW_USE_(gcc|llvm|clang) in
stdenv, which have already been marked as deprecated for some time, and
enables the HOMEBREW_CC= environment variable syntax from superenv in
stdenv.
Document --cc= in the manpage
mpich2: 3.1b1 - Add devel release.