Avoid C preprocessor trick where macro has the same name as a function.

Avoid C preprocessor trick where macro has the same name as a function.

In C, one can do preprocessor tricks by making a macro expansion include
the macro's own name.  We actually used this in the tree to automatically
provide function arguments, e.g.:

    int f(int x, const char *file, int line);
    #define f(x) f(x, __FILE__, __LINE__)

...

    f(1);    /* Expands to a call like f(1, __FILE__, __LINE__); */

However it's somewhat confusing, so this commit stops using that trick.

Reported-by: Ed Maste <emaste@freebsd.org>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Ed Maste <emaste@freebsd.org>