Make the definition for float_const() match the prototype

The definition for float_const() had int32_t, the prototype had only
int.  We only care about the sign, so int makes more sense.

float.c

@@ -827,7 +827,7 @@ static int to_float(const char *str, int s, uint8_t * result,
     return 1;                   /* success */
 }
 
-int float_const(const char *number, int32_t sign, uint8_t * result,
+int float_const(const char *number, int sign, uint8_t * result,
                 int bytes, efunc err)
 {
     error = err;