fix crash with -? aoe; fix the compile function so that
snoopy -f 'aoe(shelf = 2 && aoeata(sectors=2))' works

Reference: /n/sources/patch/applied/snoopyaoe
Date: Sat Aug  8 23:45:55 CES 2009
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/ip/snoopy/aoe.c	Sat Aug  8 23:37:50 2009
+++ /sys/src/cmd/ip/snoopy/aoe.c	Sat Aug  8 23:37:48 2009
@@ -40,10 +40,19 @@
 static void
 p_compile(Filter *f)
 {
+	Mux *m;
+
 	if(f->op == '='){
 		compile_cmp(aoe.name, f, p_fields);
 		return;
 	}
+	for(m = p_mux; m->name; m++)
+		if(strcmp(f->s, m->name) == 0){
+			f->pr = m->pr;
+			f->ulv = m->val;
+			f->subop = Ocmd;
+			return;
+		}
 	sysfatal("unknown aoe field: %s", f->s);
 }
 
@@ -95,7 +104,7 @@
 	p_filter,
 	p_seprint,
 	p_mux,
-	nil,
+	"%lud",
 	p_fields,
 	defaultframer,
 };