- Add some information about the handling of whitespace changes

- Cut a long line while here

PR:		danfe
Submitted by:	docs/116459

en_US.ISO8859-1/books/porters-handbook/book.sgml

@@ -680,8 +680,18 @@ PLIST_DIRS=     lib/X11/oneko</programlisting>
 	  <command>autoconf</command> to regenerate
 	  <command>configure</command>, do not take the diffs of
 	  <command>configure</command> (it often grows to a few thousand
-	  lines!); define <literal>USE_AUTOTOOLS=autoconf:261</literal> and take the
+	  lines!); define <literal>USE_AUTOTOOLS=autoconf:261</literal> and
-	  diffs of <filename>configure.in</filename>.</para>
+	  take the diffs of <filename>configure.in</filename>.</para>
+
+	<para>Also, try to minimize the amount of non-functional whitespace
+	  changes in your patches.  It is common in Open Source world that
+	  projects share large amount of code base, but obey different style
+	  and indenting rules.  If you take working piece of functionality from
+	  one project to fix similar area in another, please be careful: the
+	  resulting line patch may be full of non-functional changes.  It does
+	  not only increase the size of the CVS repository but makes it hard
+	  to find out what had exactly caused the problem and what did you
+	  change at all.</para>
 
 	<para>If you had to delete a file, then you can do it in the
 	  <maketarget>post-extract</maketarget> target rather than as part of