FAQ: Update to address MacOS question

A common question raised in issues and on the mailing list is whether or
not PAPI supports MacOS.

PAPI_FAQ.html

@@ -21,7 +21,8 @@ <h1>PAPI FAQ</h1><h2>General Questions (FAQ)</h2>
 <p>To subscribe to or maintain your subscription to either of the above groups, go to:<br /><a href="https://groups.google.com/a/icl.utk.edu/forum/#!forum/ptools-perfapi/join">https://groups.google.com/a/icl.utk.edu/forum/#!forum/ptools-perfapi</a>&nbsp; or <a href="https://groups.google.com/a/icl.utk.edu/forum/#!forum/perfapi-devel/join">https://groups.google.com/a/icl.utk.edu/forum/#!forum/perfapi-devel</a></p><strong>Where are the archives for the mailing lists?</strong>
 <p>The archives for the general PAPI mailing list are located at <a href="https://groups.google.com/a/icl.utk.edu/forum/#!forum/ptools-perfapi">https://groups.google.com/a/icl.utk.edu/forum/#!forum/ptools-perfapi</a>. The archives for the developers list are located at <a href="https://groups.google.com/a/icl.utk.edu/forum/#!forum/perfapi-devel">https://groups.google.com/a/icl.utk.edu/forum/#!forum/perfapi-devel</a>.</p><strong>What is needed to use PAPI?</strong>
 <p>See the Platform section at <a href="../custom/index.html?lid=62&amp;slid=96">http://icl.utk.edu/papi/custom/index.html?lid=62&amp;slid=96.</a>.</p><strong>What tools are available for PAPI?</strong>
-<p>Some of the more popular tools using PAPI can be found under the Tools link on the PAPI web page at <a href="../">http://icl.utk.edu/papi/</a>. You can also see the latest list of third party tools and related software at <a href="../links/index.html">http://icl.utk.edu/papi/links/index.html</a>. If you have a tool to be posted, send it to the mailing list.</p><br />
+<p>Some of the more popular tools using PAPI can be found under the Tools link on the PAPI web page at <a href="../">http://icl.utk.edu/papi/</a>. You can also see the latest list of third party tools and related software at <a href="../links/index.html">http://icl.utk.edu/papi/links/index.html</a>. If you have a tool to be posted, send it to the mailing list.</p><strong>Is PAPI compatible with MacOS?</strong>
+<p>No. There is no PAPI version with MacOS support for CPU hardware counter monitoring. This is due to MacOS not exporting counters that PAPI can read.</p><br />
 <h2>The PAPI Library</h2>
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