Removed casts from ngx_memcmp() macro. Casts are believed to be not needed, since memcmp() has "const void *" arguments since introduction of the "void" type in C89. And on pre-C89 platforms nginx is unlikely to compile without warnings anyway, as there are no casts in memcpy() and memmove() calls. These casts were added in 1648:89a47f19b9ec without any details on why they were added, and Igor does not remember details either. The most plausible explanation is that they were copied from ngx_strcmp() and were not really needed even at that time. Prodded by Alejandro Colomar.