Fixed warnings - strict-prototypes (#155)

Signed-off-by: Alejandro Hernández Cordero <ahcorde@gmail.com>

rosidl_typesupport_c/test/test_type_support.c

@@ -22,11 +22,11 @@
 // function still needs to be defined separately. Windows has gotten picky with its compiler
 // warnings recently.
 #if defined _WIN32 || defined __CYGWIN__
-__declspec(dllexport) const rosidl_message_type_support_t * test_message_type_support();
-__declspec(dllexport) const rosidl_service_type_support_t * test_service_type_support();
+__declspec(dllexport) const rosidl_message_type_support_t * test_message_type_support(void);
+__declspec(dllexport) const rosidl_service_type_support_t * test_service_type_support(void);
 #else
-const rosidl_message_type_support_t * test_message_type_support();
-const rosidl_service_type_support_t * test_service_type_support();
+const rosidl_message_type_support_t * test_message_type_support(void);
+const rosidl_service_type_support_t * test_service_type_support(void);
 #endif
 
 static const rosidl_message_type_support_t message_type_support = {
@@ -37,6 +37,12 @@ static const rosidl_service_type_support_t service_type_support = {
   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 
-const rosidl_message_type_support_t * test_message_type_support() {return &message_type_support;}
+const rosidl_message_type_support_t * test_message_type_support(void)
+{
+  return &message_type_support;
+}
 
-const rosidl_service_type_support_t * test_service_type_support() {return &service_type_support;}
+const rosidl_service_type_support_t * test_service_type_support(void)
+{
+  return &service_type_support;
+}