patch 9.0.1224: cannot call a :def function with a number for float argument

Problem:    Cannot call a :def function with a number for a float argument.
Solution:   Accept a number as well, convert it to a float.
diff --git a/src/structs.h b/src/structs.h
index a015dec..3b5a233 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -1462,10 +1462,11 @@
 
 #define TTFLAG_VARARGS	    0x01    // func args ends with "..."
 #define TTFLAG_BOOL_OK	    0x02    // can be converted to bool
-#define TTFLAG_NUMBER_OK    0x04    // tt_type is VAR_FLOAT, VAR_NUMBER is OK
-#define TTFLAG_STATIC	    0x08    // one of the static types, e.g. t_any
-#define TTFLAG_CONST	    0x10    // cannot be changed
-#define TTFLAG_SUPER	    0x20    // object from "super".
+#define TTFLAG_FLOAT_OK	    0x04    // number can be used/converted to float
+#define TTFLAG_NUMBER_OK    0x08    // number can be used for a float
+#define TTFLAG_STATIC	    0x10    // one of the static types, e.g. t_any
+#define TTFLAG_CONST	    0x20    // cannot be changed
+#define TTFLAG_SUPER	    0x40    // object from "super".
 
 typedef enum {
     ACCESS_PRIVATE,	// read/write only inside th class