I'm not sure why I thought reinventing object instantiation was a good
idea.

We only need one copy of each of these strings, not ~7500.

The default arguments were removed from these methods long ago, so
nothing is standing in the way of using define_method here.

Closes Homebrew/homebrew#28560.

Due to the fragility of the code, this functionality was removed in
recent refactorings of the tap code.

It is possible to restore these features, but it needs to be done in
a cleaner, more maintainable way.

Closes Homebrew/homebrew#29585.

Formula#path can no longer be a symlink.

No Xcode 5.1 support.

Closes Homebrew/homebrew#29488.

As per 9ab605c7f1883 removal of `brew dirty`. `--multiple` *implies*
`--versions`, thus IMO it shouldn't be necessary to also explicitly
include the `--versions` option, but that's a separate matter. For now
this offers the small added convenience of:

    $ brew list --m<TAB><TAB>

to quickly expand the `brew dirty` equivalent.

Closes Homebrew/homebrew#29571.

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

Closes Homebrew/homebrew#29555.

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

Closes Homebrew/homebrew#29476.

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

'-fno-tree-pre' and '-fno-tree-dominator-opts'

Closes Homebrew/homebrew#29452.

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

Fixes Homebrew/homebrew#28765.

Closes Homebrew/homebrew#29377.

Although the correct sysroot is built into Apple's tools on 10.9, we
need to continue setting it for custom compilers.

I found the dual use of CMAKE_*_PATH variables to make it difficult to
reason about this code. Now a separate set of variables are used to
communicate with the cc wrapper, and less work is performed in the
wrapper itself.

We no longer pass the SDK include path as a -isystem directory on
Xcode-only setups. Doing so is redundant with `--sysroot` and has other
side effects, namely changing the include path search order, which can
break compilation of some software (e.g. qemu).

On Xcode-only 10.9, we can additionally omit `--sysroot`, as the correct
paths are built into the tools.

A new variable, HOMEBREW_SYSROOT, is used to this information to the
wrapper. It will be unset on Xcode-only 10.9. HOMEBREW_SDKROOT will
continue to be set, as it is used for other things besides setting the
include search path.

Closes Homebrew/homebrew#29379.

Closes Homebrew/homebrew#29380.

Closes Homebrew/homebrew#29318.