[PATCH] index: add NetBSD, Homebrew, and pkgsrc to "Obtaining Notmuch"

[J. Lewis Muir]

Add NetBSD to the distribution list in the "Obtaining Notmuch" section.
Add Homebrew and pkgsrc to the list of third-party package managers for
OS X.  Remove the word "Mac" from "Mac OS X" to get just "OS X" which
matches Apple's official naming.
---
 index.mdwn | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/index.mdwn b/index.mdwn
index 742f482..1518624 100644
--- a/index.mdwn
+++ b/index.mdwn
@@ -93,11 +93,12 @@ Notmuch is packaged for at least the following distributions:
 * [Debian](http://packages.debian.org/search?keywords=notmuch)
 * [Fedora](https://apps.fedoraproject.org/packages/notmuch)
 * [Gentoo](http://packages.gentoo.org/package/net-mail/notmuch)
+* [NetBSD](http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/mail/notmuch/README.html)
 * [openSUSE](https://build.opensuse.org/search?search_text=notmuch)
 * [Slackware](http://slackbuilds.org/repository/13.37/office/notmuch/)
 * [Ubuntu](http://packages.ubuntu.com/search?keywords=notmuch)
 
-Notmuch can be installed on Mac OS X using [MacPorts](https://www.macports.org/ports.php?by=name&substr=notmuch).
+Notmuch can be installed on OS X using [Homebrew](https://github.com/Homebrew/homebrew/blob/master/Library/Formula/notmuch.rb), [MacPorts](https://www.macports.org/ports.php?by=name&substr=notmuch), or [pkgsrc](http://ftp.netbsd.org/pub/pkgsrc/current/pkgsrc/mail/notmuch/README.html).
 
 ## Development and Contributing
 
-- 
2.3.2 (Apple Git-55)