我正在尝试使用 brew 安装 htop：
? ~ brew install htop
Error: You must `brew link autoconf' before htop-osx can be installed
然后我在做
brew link autoconf
Linking /usr/local/Cellar/autoconf/2.69... Warning: Could not link autoconf. Unlinking...
Error: Could not symlink file: /usr/local/Cellar/autoconf/2.69/share/emacs/site-lisp/autotest-mode.elc
Target /usr/local/share/emacs/site-lisp/autotest-mode.elc already exists. You may need to delete it.
To force the link and overwrite all other conflicting files, do:
brew link --overwrite formula_name
To list all files that would be deleted:
brew link --overwrite --dry-run formula_name
问题的根源是什么？