Fix CLT detection on Mavericks/Xcode5

On Mavericks/Xcode5 machines the Command Line Tools are shipped directly
with Xcode. Detect the corret path to the tools in this case.

cc is just a symlink to clang so use gcc as toolname.
The include files are in the SDK path now. Get this path using xcrun.

Signed-off-by: Christoph Kassen <christoph@kassen.name>
Merge branch 'master' of github.com:ckassen/homebrew

# By Steffen Matthischke (2) and others
# Via Adam Vandenberg
* 'master' of github.com:ckassen/homebrew:
  lcdf-typetools: bugfix patch for Xcode 5 / 10.9
  google-perftools: add note about patch
  google-perftools: add missing #include
  ArangoDB 1.4.0
  gradle 1.9-rc2
  mdbtools 0.7.1
  unrar 5.0.12
  Use curl to download list of Apache mirrors
  rp 1.0
  add unlink apps to manpage and completion
  New command: `brew unlinkapps`
  class-dump 3.4 & HEAD
  speedtest_cli 0.2.2
  x265 0.5
  binwalk 1.2.2-1
  libvirt: Fix Mavericks build issues
  ShivaVG 0.2.1
  ruby-build: depends on openssl and libyaml
  ruby-build v20131030