我在全新的Mac上安装了一些Homebrew软件包。但是，链接时会出现一些错误：
ln: ./libsvn_wc-1.dylib: Permission denied
Error: The linking step did not complete successfully
The package built, but is not symlinked into /usr/local
You can try again using `brew link subversion'
Error: Could not create symlink /usr/local/lib/libsvn_wc-1.dylib.
Check that you have permssions on /usr/local/lib
==> Summary
/usr/local/Cellar/subversion/1.6.15: 88 files, 6.0M, built in 38 seconds
因此，SVN并未真正正确安装，如下所示：
charon:~ werner$ which svn
/usr/bin/svn
Git的相同错误：
charon:~ werner$ brew link git
Error: Permission denied - /usr/local/lib/python2.6
但是，这个已正确安装：
charon:~ werner$ which git
/usr/local/bin/git
我应该只是chmod在lib目录或者是还有什么我应该做的最好？
charon:~ werner$ ls -l /usr/local/
total 8
drwxr-xr-x 7 werner staff 238 Mar 8 15:58 Cellar
drwxr-xr-x 6 werner staff 204 Mar 8 14:21 Library
-rw-r--r-- 1 werner staff 1614 Mar 8 14:21 README.md
drwxr-xr-x 56 werner staff 1904 Mar 8 15:59 bin
drwxr-xr-x 4 werner staff 136 Mar 8 15:46 etc
drwxr-xr-x 3 werner staff 102 Mar 8 15:59 include
drwxr-xr-x 3 root wheel 102 Apr 17 2010 lib
drwxr-xr-x 12 werner staff 408 Mar 8 15:57 share
drwxr-xr-x 4 root wheel 136 Mar 8 14:43 texlive