Remove configure check for bcopy(), no longer required

This fixes building on Haiku OS (where bcopy() is a macro, not a function).

include/defs.h.in

@@ -1,8 +1,5 @@
 /* include/defs.h.in.  Generated from configure.in by autoheader.  */
 
-/* Define this if bcopy is declared in string.h. */
-#undef BCOPY_DECLARED
-
 /* Define to one of `_getb67', `GETB67', `getb67' for Cray-2 and Cray-YMP
    systems. This function is required for `alloca.c' support on those systems.
    */

include/irc_std.h

@@ -204,10 +204,6 @@ int	killpg (int pgrp, int sig);
 char *	getpass (const char * prompt);
 #endif
 
-#ifndef BCOPY_DECLARED
-void	bcopy (const void *src, void *dest, size_t n);
-#endif
-
 #define BUILT_IN_COMMAND(x) \
 	void x (char *command, char *args, char *subargs, char *helparg)