Fix LLVM sha1/version number. Add compiler-rt to build.

This updates the sha1 of the LLVM package - it was probably silently updated without bumping the version. LLVM developers don't backport fixes or address existing regressions after the release, by creating a point release. As a result, things like this happen when critical fixes go out.

It also has a patch to fix the version and change it from `3.2svn` to `3.2`. This fixes #17034. There's a comment with the bugzilla ID. It has yet to be resolved.

This patch also adds `compiler-rt` to the build, which is now a recommended component of the LLVM project. In particular, it features asan and the blocks runtime. It should be useful in general (LLVM clients could annotate IR to use asan for example,) and as a bonus if you install clang, it's a great bug catcher with `-fsanitize=address`:

```
$ cat asan.c
#include <stdlib.h>
int main() {
  char *x = (char*)malloc(10 * sizeof(char*));
  free(x);
  return x[5];
}
$ /usr/local/Cellar/llvm/3.2/bin/clang -fsanitize=address asan.c
$ ./a.out
=================================================================
==14637== ERROR: AddressSanitizer: heap-use-after-free on address 0x00010dafdf45 at pc 0x10b826dae bp 0x7fff543d90f0 sp 0x7fff543d90e8
READ of size 1 at 0x00010dafdf45 thread T0
    #0 0x10b826dad (/Users/a/t/./a.out+0x100000dad)
    #1 0x7fff8ae2f7e0 (/usr/lib/system/libdyld.dylib+0x27e0)
    #2 0x0
0x00010dafdf45 is located 5 bytes inside of 80-byte region [0x00010dafdf40,0x00010dafdf90)
freed by thread T0 here:
    #0 0x10b82f7a8 (/Users/a/t/./a.out+0x1000097a8)
    #1 0x10b82ee22 (/Users/a/t/./a.out+0x100008e22)
    #2 0x10b826d27 (/Users/a/t/./a.out+0x100000d27)
    #3 0x7fff8ae2f7e0 (/usr/lib/system/libdyld.dylib+0x27e0)
    #4 0x0
previously allocated by thread T0 here:
    #0 0x10b82f59c (/Users/a/t/./a.out+0x10000959c)
    #1 0x7fff911e9152 (/usr/lib/system/libsystem_c.dylib+0x2d152)
    #2 0x7fff911e9ba6 (/usr/lib/system/libsystem_c.dylib+0x2dba6)
    #3 0x10b826ce4 (/Users/a/t/./a.out+0x100000ce4)
...
lots more output
```

The bottles will need to be rebuilt, and I don't know who's responsible for that.