Patch: dependency tracking info

[Tom Tromey]

I'm checking this in to the web pages.
It adds a note about another dependency tracking pitfall.

Tom

Index: dependencies.html
===================================================================
RCS file: /cvs/automake/htdocs/dependencies.html,v
retrieving revision 1.1
diff -u -r1.1 dependencies.html
--- dependencies.html 2001/06/30 00:08:11 1.1
+++ dependencies.html 2001/07/14 23:56:20
@@ -198,6 +198,22 @@
      modifying dependency generators to record every probe, instead of
      every successful open.<p>
 
+<li> <p>Since automake generates dependencies as a side effect of
+     compilation, there is a bootstrapping problem when header files
+     are generated by running a program.  The problem is that, the
+     first time the build is done, there is no way by default to know
+     that the headers are required, so make might try to run a
+     compilation for which the headers have not yet been built.</p>
+
+     <p>This was also a problem in the previous dependency tracking
+     implementation.</p>
+
+     <p>The current fix is to use <tt>BUILT_SOURCES</tt> to list built
+     headers.  This causes them to be built before any other
+     other build rules are run.  This is unsatisfactory as a general
+     solution, however in practice it seems sufficient for most actual
+     programs.</p>
+
 </ul>
 
 <p>This code has not yet been in an official release of Automake.  So,