The beginnings of some decent API documentation.

Also, tweak `.yardopts` to better fix our internal style.

 - use a regexp literal and avoid escaping forward slashes
 - escape the period in "github.com"
 - match only hex characters in the commit part
 - allow hyphen in usernames and repo names, matching what we allow for
   tap names
 - avoid unnecessary capture

Closes Homebrew/linuxbrew#103

Closes Homebrew/homebrew#30830.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Closes Homebrew/homebrew#29139.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Newer versions of Ruby issue a warning for repeated character classes.

This commit supports "-" and "_" in names of user and repository.

Closes Homebrew/homebrew#28203.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Closes Homebrew/homebrew#23430.

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

Update version due to recent compiler selection fixes.

Still in alpha state.
Handles defaults and merging changes with new versions.
Enable by setting the HOMEBREW_GIT_ETC environment variable.

Closes Homebrew/homebrew#15751.
Closes Homebrew/homebrew#17713.

On Unix, the path separator is ':', whereas on Windows,
it is ';'. This is the first of a series of patch to bring
macbrew's and winbrew's codebases closer together.

The main places the magic constant ':' was being used were:
  - the $PATH environment variable
  - CMAKE-related environment variables
  - pkg-config related environment variables

Closes Homebrew/homebrew#21921.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

Closes Homebrew/homebrew#20318.

Closes Homebrew/homebrew#20239.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>

This was meant to support:

  env do |req|
    append_path 'PATH', req.some_method
    ...
  end

i.e., the block was evaluated in the context of ENV. But it turned out
to be not so useful after all, so I'm ripping it out before something
actually depends on it.

Allows access to the Ruby path. Needed for Linux
porting.