Variable for path to SDK root

[Ned Deily]

In article <l5enmp$s8a$1 at ger.gmane.org>,
 Jann Roder <mail at jann-roeder.net> wrote:

> /usr/include doesn't exist on Mavericks. Its content is now at
> /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer
> /SDKs/MacOSX10.9.sdk/usr/include/

That's not true.  You have to properly install the Command Line Tools package, 
just like you have to on earlier OS X releases.  What's changed with Mavericks 
is *how* you install the CLT.  The most reliable way on 10.9 should be:

xcode-select --install

-- 
 Ned Deily,
 nad at acm.org