> Does anyone think this is a desirable feature?
> If I fix it, is anything else likely to break?

This change stops the problem with .OPTIONAL files.

Index: suff.c
===================================================================
RCS file: /cvsroot/src/usr.bin/make/suff.c,v
retrieving revision 1.43
diff -u -p -r1.43 suff.c
--- suff.c	2004/01/11 17:24:25	1.43
+++ suff.c	2004/01/11 17:28:24
@@ -1425,6 +1425,16 @@ SuffFindCmds(Src *targ, Lst slst)
 	}
 	s = (GNode *)Lst_Datum (ln);
 
+	if (s->type & OP_OPTIONAL) {
+	    /*
+	     * We haven't looked to see if .OPTIONAL files exist yet, so
+	     * don't use one as the implicit source.
+	     * Needed for rules from .depend files when the source file
+	     * has been moved.
+	     */
+	    continue;
+	}
+
 	cp = strrchr (s->name, '/');
 	if (cp == (char *)NULL) {
 	    cp = s->name;

The entire purpose of SuffFindCmds() seems to be to locate the
wrong .c file :-(

	David

-- 
David Laight: david@l8s.co.uk