"warning #711: ellipsis with no explicit parameters is nonstandard" with "-strict-ansi"

Hello,

With upgrade to icc18.0.1 the following warning appears when "-strict-ansi" argument is supplied:

icc18_toupper_test.c(6): warning #711: ellipsis with no explicit parameters is nonstandard
  	v = toupper(v);
  	    ^

With icc15 this message did not appear.

Compiler  is installed x86_64 Linux.

The code is attached, compilation cmd:
icc -strict-ansi cc18_toupper_test.c

How do I get rid of this warning?

Thanks