PR c/21759
        * c.opt (Wc++-compat): New.
        * doc/invoke.texi (-Wc++-compat): Document.
        * c-typeck.c (convert_for_assignment): Check for implicit
        conversion void* -> T*.
testsuite/
        * gcc.dg/Wcxx-compat-1.c: New.

From-SVN: r100806