C++-mode: Syntax highlighting: wrong color for function identifier depending on the kind of whitespace that follows

[Erik]

In GNU Emacs 21.3.1 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)

In C++-mode, type:
void function(int x);

The string "function" is blue, which is correct. Now type:
void function           (int x);

The color is still correct. But type:
void function
                        (int x);

The color is suddenly yellow. This is clearly a bug. It seems to happen when
the whitespace between the function identifier th and argument list includes a
newline. The color of function identifiers should always be the same, and not
depend on what kind of whitespace follows it.