move cabal on OSX stuff to its own page

doc/install/OSX.mdwn

@@ -32,4 +32,8 @@ git-annex is now [[available in Homebrew|Homebrew]]!
 ## using MacPorts
 
 git-annex is not available in MacPorts, but can be built from source using
-MacPorts tools. See [[MacPorts]]
+MacPorts tools. See [[MacPorts]].
+
+## building it yourself
+
+See [[cabal]].

doc/install/OSX/cabal.mdwn

@@ -0,0 +1,6 @@
+If you cannot get a OSX build of git-annex suitable for your computer,
+from eg [[HomeBrew]] or the regular [[OSX]] prebuilt app, you
+can try Building git-annex from source on OSX, using haskell's cabal package
+manager.
+
+For general instructions for using cabal, see [[this page|/install/cabal]].

doc/install/OSX/comment_4_bbe99673033e4c48c8bb3db24ee419f9._comment

@@ -1,8 +0,0 @@
-[[!comment format=mdwn
- username="https://www.google.com/accounts/o8/id?id=AItOawkSq2FDpK2n66QRUxtqqdbyDuwgbQmUWus"
- nickname="Jimmy"
- subject="comment 4"
- date="2012-12-10T17:00:43Z"
- content="""
-For those that care, I've updated my autobuilder to the latest version of haskell-platform 2012.4.0.0 and it appears to be building correctly.
-"""]]