Sandboxing llvm formulae and other improvements.

* Put everything in #{prefix}/lib/llvm-#{version}, exception python
  bindings and utility tools.
  - Update path in caveats.
* Suffix binaries with version and symlink to #{bin} to avoid
  conflicts.
  - Not marked as keg_only any more.
  - Also version python bindings.
* llvm33: Add option to build libc++ and ship to location as per
  upstream Makefile.
  - Also update caveat about how to use the included libc++.
* llvm32, llvm33: Add polly support.
  - Build depends on gmp4, isl011, cloog018.
* Drop head links. Development release will be introduced in dedicated
  formula.
* Other formula clean-ups.
* Also make caveats more consistent.
Use new universal archs for llvm formulae.
Only install Clang python bindings when Clang is enabled.
Use man1 helpers.
gcc49: snapshot 20130825.
llvm 3.4

I added formula for LLVM 3.4.
LLVM 3.4 is now in-progress and I couldn't find snapshot archives like
gcc weekly snapshots. So I decided to use the latest source code from
repositories.

Closes #192.

Signed-off-by: Xiyue Deng <manphiz@gmail.com>
llvm34: use general universal archs.
llvm34: depends on gmp/isl/cloog from core.

* Recently llvm34 starts requiring isl 0.12+.

Closes #195.
Node 0.8.25

Closes #197.

Signed-off-by: Xiyue Deng <manphiz@gmail.com>
Use macports links for GCC patches.

* Apply for gcc4{3,4,5}.
Fix llvm34 version suffix.

* When building HEAD, the version variable is actually "HEAD". Force to
  use 3.4 instead.
Revert "Fix llvm34 version suffix."

This reverts commit eb572998b8fa2e780f359834ca12ddccbeaf02fa.
Remove version numbers from llvm34.

* Head doesn't support version and set it to "HEAD" unconditionally.
Fix instruction to use built libc++.

* Added "-lc++" to actually link to the built libc++.
  - Apply to llvm3{3,4}.
llvm3{3,4}: support --enable-ffi build option

This option to ./configure depends on libffi and enables calling native
functions from interpreted LLVM bitcode.

Closes #200.

Signed-off-by: Xiyue Deng <manphiz@gmail.com>
isl011: various fixes.

* Correct gmp4 prefix. Was "gmp" by mistake.
* Update homepage link.
* Drop head (not useful for formulae in homebrew-versions).
* Use "--disable-silent-rules" to enable verbose build log.