[trunk] remove some simple warnings about unused params

tests/unit/testempty0.c

@@ -1,3 +1,7 @@
 #include "openjpeg.h"
 
-int main(int argc, char **argv) { return 0; }
+int main(int argc, char **argv) {
+  (void)argc;
+  (void)argv;
+  return 0; 
+}