Fix RETURNFUNC -- when RETURNFUNC(function) was used is was calling the function multiple times

https://github.com/Hamlib/Hamlib/issues/595

src/misc.h

@@ -142,9 +142,12 @@ extern HAMLIB_EXPORT(int) parse_hoststr(char *host, char hoststr[256], char port
 void errmsg(int err, char *s, const char *func, const char *file, int line);
 #define ERRMSG(err, s) errmsg(err,  s, __func__, __FILENAME__, __LINE__)
 #define ENTERFUNC rig_debug(RIG_DEBUG_VERBOSE, "%s(%d):%s entered\n", __FILENAME__, __LINE__, __func__)
+// we need to refer to rc just once as it 
+// could be a function call 
 #define RETURNFUNC(rc) do { \
-                        rig_debug(RIG_DEBUG_VERBOSE, "%s(%d):%s return(%ld)\n", __FILENAME__, __LINE__, __func__, (long int) (rc)); \
-                        return (rc); \
+			            int rctmp = rc; \
+                        rig_debug(RIG_DEBUG_VERBOSE, "%s(%d):%s return(%ld)\n", __FILENAME__, __LINE__, __func__, (long int) (rctmp)); \
+                        return (rctmp); \
                        } while(0)
 
 #if 0 // 5.0