Rename some BUF_xxx to OPENSSL_xxx

Rename BUF_{strdup,strlcat,strlcpy,memdup,strndup,strnlen}
to OPENSSL_{strdup,strlcat,strlcpy,memdup,strndup,strnlen}
Add #define's for the old names.
Add CRYPTO_{memdup,strndup}, called by OPENSSL_{memdup,strndup} macros.

Reviewed-by: Tim Hudson <tjh@openssl.org>

engines/e_chil.c

@@ -476,7 +476,7 @@ static const char *get_HWCRHK_LIBNAME(void)
 static long set_HWCRHK_LIBNAME(const char *name)
 {
     free_HWCRHK_LIBNAME();
-    return (((HWCRHK_LIBNAME = BUF_strdup(name)) != NULL) ? 1 : 0);
+    return (((HWCRHK_LIBNAME = OPENSSL_strdup(name)) != NULL) ? 1 : 0);
 }
 
 static const char *n_hwcrhk_Init = "HWCryptoHook_Init";