Remove HAVE_MEMCPY ifdefs

memcpy(3) has been in standard C since C89.  It is also in
POSIX.1-2001, in SVr4, and in 4.3BSD (see memcpy(3) and memcpy(3p)).
We can assume that this function is always available.

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>

lib/defines.h

@@ -70,10 +70,6 @@ extern char * textdomain (const char * domainname);
 #  define strrchr rindex
 # endif
 char *strchr (), *strrchr (), *strtok ();
-
-# ifndef HAVE_MEMCPY
-#  define memcpy(d, s, n) bcopy((s), (d), (n))
-# endif
 #endif				/* not STDC_HEADERS */
 
 #if HAVE_ERRNO_H