Closes Homebrew/homebrew#9199.

Please check for regressions. I was careful, but there was a lot of stuff.

Closes Homebrew/homebrew#9409.

So you can source `brew --env` to make it easier to build your own software, etc.

Fixes Homebrew/homebrew#10598.

Ideally we would show a message for builds that use xcodebuild etc. But there is no easy mechanism for this in place.

About time we did this right?

Some build scripts want to inspect the git history, e.g. to determine
version strings. Rather than copy the repository into the build tree,
just setting GIT_DIR is enough for things to "just work".

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

This reverts commit 21acfc1c7e66babf112196812fdfcf442edf3a97.

This was reverted because we tried to leave /usr/local with root permissions, but
this caused problems for us. Sorry Rogue Amoeba. I'd suggest not installing your
App's tools into /usr/local. It's outside your App's domain, so you can't be sure
what will happen there.

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

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

This should mean all those formula that pass options to aclocal don't need to anymore, but I'm not risking changing them.

We need these now for Xcode-4.3/CLT4X installations.

Also prevent m4 error in installer. And prevent brew doctor complaining if we're Xcode 4.3 or above.

Closes Homebrew/homebrew#10349. Fixes Homebrew/homebrew#10423. Refs Homebrew/homebrew#9179.

Apply the 'bin' audit to 'sbin' too, and also complain if subfolders are
installed to either.

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

Closes Homebrew/homebrew#10460.

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

Now individual formulae don't need to require this if they want to use
Hardware methods outside of `def install`.

* Chicken Scheme
* Node.js
* Rubinius

Closes Homebrew/homebrew#8466.

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

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

There are still methods and variables with the word "folder" in the
name, but at least user-facing messages and warnings should use the
correct terminology.

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

This prevents passing nested arrays to exec; the same thing is done in
safe_system.

Fixes Homebrew/homebrew#10295.

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

We set defaults for C and C++, might as well do the same for Objective-C and
Objective-C++.

Closes Homebrew/homebrew#10354.

fixes a problem with the opencv formula

Closes Homebrew/homebrew#10291.

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

The correct location for it IMO. Also added warning for the user.