issue a incomplete structure diagnostic when an incomplete
structure is used as the last element of a structure.

Reference: /n/sources/patch/applied/incmpltdiag
Date: Wed Sep 16 00:14:42 CES 2009
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/cc/dcl.c	Wed Sep 16 00:13:57 2009
+++ /sys/src/cmd/cc/dcl.c	Wed Sep 16 00:13:54 2009
@@ -541,7 +541,7 @@
 				l->offset = o;
 			} else {
 				if(l->width <= 0)
-				if(l->down != T)
+				if(l->down != T || l->width < 0)
 					if(l->sym)
 						diag(Z, "incomplete structure element: %s",
 							l->sym->name);