keep usage definition above main in ubase

ps.c

@@ -12,7 +12,6 @@
 #include "proc.h"
 #include "util.h"
 
-static void usage(void);
 static void psout(struct procstat *ps);
 static void psr(const char *file);
 
@@ -23,6 +22,12 @@ enum {
 	PS_fflag = 1 << 3
 };
 
+static void
+usage(void)
+{
+	eprintf("usage: [-aAdef] %s\n", argv0);
+}
+
 static int flags;
 
 int
@@ -56,12 +61,6 @@ main(int argc, char *argv[])
 	return EXIT_SUCCESS;
 }
 
-static void
-usage(void)
-{
-	eprintf("usage: [-aAdef] %s\n", argv0);
-}
-
 static void
 psout(struct procstat *ps)
 {