mscanf() introduces a leading \n newline and the prompt before prompting the user for input

Reported by Samuel GOUGEON (@sgougeon)

BUG DESCRIPTION:
----------------
In Scilab 4.1.2, we had:
-----------------------
-->mprintf("abcd"); mprintf("efgh");
abcdefgh   // so mprintf() does not append any \n. Now:
-->mprintf("message:"); i = mscanf("%s")
message:-->abcd    // We are prompted on the same line: OK (but the prompt should be "" or not here)
 i  =

 abcd     // OK

-->

In Scilab 5.5 and 6.0.0:
-----------------------
--> mprintf("abcd"); mprintf("efgh");
abcdefgh                                   // OK: same as always
--> mprintf("message:"); i = mscanf("%s")
message:                 // Now, a \n is introduced before prompting = BUG
--> abcd
 i  = 


 abcd

-->
 
ERROR LOG:
----------
none. Wrong behavior

HOW TO REPRODUCE THE BUG:
-------------------------
mprintf("abcd"); mprintf("efgh");
mprintf("message:"); i = mscanf("%s")

OTHER INFORMATION:
------------------
This hinders the input() behavior.
Scilab is a high level language. It is strange to have such a bug on a
so standard feature, not working properly.