InstallationError: don't search issues on < 1.8.6

open-uri on Ruby pre-1.8.6 simply will not open https URLs at all,
making it impossible to check the Github API using the same method
as Homebrew.

This may only be disabled temporarily until the issue search is
rewritten, for example to use the curl helper.
cairo: depend on freetype when building without X

harfbuzz won't build without cairo-ft.
Allow gcc-4.2 in HOMEBREW_CC

Fixes:

$ HOMEBREW_CC=gcc brew irb
...
irb(main):001:0> require 'superenv'
=> true
irb(main):002:0> ENV.setup_build_environment
=> nil
irb(main):003:0> ENV.setup_build_environment
Warning: Invalid value for HOMEBREW_CC: gcc-4.2
Python 2.x and 3.x support

New `depends_on :python` Dependency.
New `depends_on :python3` Dependency.

To avoid having multiple formulae with endings -py2 and -py3,
we will handle support for different pythons (2.x vs. 3.x)
in the same formula.
Further brewed vs. external python will be transparently supported.

The formula also gets a new object `python`, which is false if
no Python is available or the user has disabled it. Otherwise
it is defined and provides several support methods:

python.site_packages # the site-packages in the formula's Cellar
python.global_site_packages
python.binary # the full path to the python binary
python.prefix
python.version
python.version.major
python.version.minor
python.xy # => e.g. "python2.7"
python.incdir # includes of python
python.libdir # the python dylib library
python.pkg_config_path # used internally by brew
python.from_osx?
python.framework?
python.universal?
python.pypy?
python.standard_caveats # Text to set PYTHONPATH for python.from_osx?
python.if3then3 # => "" for 2.x and to "3" for 3.x.

Further, to avoid code duplication, `python` takes an optional
block that is run twice if the formula defines depends_on
:python AND :python3.

python do
  system python, 'setup.py', "--prefix=#{prefix}"
end

Read more in the Homebrew wiki.
superenv: Work if build tool changes DEVELOPER_DIR

Some build systems still set the DEVELOPER_DIR to /Developer
and then nothing works any more (xcrun, xcodebuild etc.)
I am looking at you MacVim.
tsung 1.5

Closes #20227.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
heroku-toolbelt 2.39.4

Closes #20221.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
MySQL Cluster 7.3.1

Closes #20214.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
cppcheck 1.60.1

Closes #20222.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
mercurial: XCode-only system py: Find Python.h

Fix #18517
depends_on :python Default to min vers 2.6 not 2.7

To support system python on OS X
brew-test-bot: skip unresolvable dependencies.
make erlang versions case-insensitive for bottles.
MacVim: Don't hardcode --with-macsdk

Instead only pass the --with-macsdk if on XCode-only.

Fix #20229
macvim: style
Remove empty test file

This breaks my test runner in weird ways.
Fix (Python) language dependency test

System python (for 2.x) does not provide `python2` binary.
So use `python` again.

For Python 3.x we still use `python3`.
mercurial: Style bit
gtk-doc: Needs libxml2 to be built --with-python

Fix #20150
libsass: silent version update

Closes #20230.