FAQ 4 and 5 suggestions

1) A few weeks ago, Steven Gerber had problems with i386 to amd64 binary 
conversion, it is mentioned in the FAQ. This diff just highlights it more. 
IMHO, it should mention somewehre right when they are going to install.
I am just paraphrasing what happened in those conversations a little bit.
Please feel free to shift it somewhere more appropriate/modify/reject

faq4 + faq12

Index: faq4.html
===================================================================
RCS file: /cvs/www/faq/faq4.html,v
retrieving revision 1.306
diff -u -r1.306 faq4.html
--- faq4.html	7 Nov 2010 03:19:36 -0000	1.306
+++ faq4.html	20 Apr 2011 19:45:08 -0000
@@ -537,6 +537,9 @@
 <a name="InstStart"></a>
 <h3>4.5.1 - Starting the install</h3>
 <!-- XXXrelease -->
+Note: If you have previously installed i386 on a machine and now want to 
+install amd64 or vice versa, please read about 
+<a href="http://www.openbsd.org/faq/faq12.html#amd64i386bin">possible install issues.</a>
 Whatever your means of booting is, it is now time to use it.  During
 the boot process, the kernel and all of the programs used to install
 OpenBSD are loaded into memory.


Index: faq12.html
===================================================================
RCS file: /cvs/www/faq/faq12.html,v
retrieving revision 1.101
diff -u -r1.101 faq12.html
--- faq12.html	11 Jun 2010 01:03:49 -0000	1.101
+++ faq12.html	20 Apr 2011 19:52:50 -0000
@@ -313,11 +313,13 @@
 
 <a name="amd64i386bin"></a>
 <h3>12.3.2 - Can I run my i386 binary on OpenBSD/amd64?</h3>
+Or can I run my amd64 binary on i386?
+
 No.
 
 <p>
 OpenBSD/amd64 is a totally separate platform from OpenBSD/i386, and at
-this point, no binary compatibility is provided.
+this point, no binary compatibility is provided between them.
 As OpenBSD encourages open source applications, there is not much
 interest in binary compatibility across platforms with developers.
 
@@ -325,7 +327,8 @@
 Note that the OpenBSD/amd64 and OpenBSD/i386 boot loaders will
 load each other's kernels, making it easier to reinstall a system with the
 "other" platform.
-However, it has to be a complete "wipe and reinstall" operation -- left-over
+However, it has to be a complete "wipe and reinstall" operation. Note you 
+might get away with it for some time but eventually left-over
 binaries from the "previous" installation will most likely make your life
 unpleasant.
 


2) It should be noted in the FAQ that it is good practice to clean out the 
kernel compile occasionally or always. This will cut down the misc@ 
requests when config changes, makefile changes or compiler changes etc.. 
Feel free to accept/modify or reject.

Index: faq5.html
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RCS file: /cvs/www/faq/faq5.html,v
retrieving revision 1.184
diff -u -r1.184 faq5.html
--- faq5.html	4 Apr 2011 11:08:30 -0000	1.184
+++ faq5.html	20 Apr 2011 19:46:06 -0000
@@ -648,6 +648,8 @@
 For this example, we will assume you are using the i386 platform:
 
 <blockquote><pre>
+# <b>rm /usr/src/sys/arch/i386/compile/GENERIC/*</b>
+# <b>rmdir /usr/src/sys/arch/i386/compile/GENERIC</b>
 # <b>cd /usr/src/sys/arch/i386/conf</b>
 # <b>config GENERIC</b>
 # <b>cd ../compile/GENERIC</b>
@@ -656,7 +658,8 @@
 # <b>make install</b>
 </pre></blockquote>
 
-Replace "<tt>i386</tt>" in the first line with your platform name.
+The first two lines remove any previous leftover kernel configuration.
+Replace "<tt>i386</tt>" in the above lines with your platform name.
 The 
 <a href="http://www.openbsd.org/cgi-bin/man.cgi?query=machine&amp;sektion=1">machine(1)</a>
 command can tell you what your platform name is, so an obvious