scripts/gcc: Canadian Cross skip -print-multi-lib log output

Attempting to ${CT_TARGET}-gcc -print-multi-lib will fail

In do_cc_core_backend, for the final compiler in a canadian cross
baremetal, warn that multi-libs cannot be determined

In do_cc_backend, for either final compiler for a canadian cross,
warn that multi-libs cannot be determined

(Plus fixed CT_PREFIX_DIR in do_cc_backend to be ${prefix})

Signed-off-by: "David Holsgrove" <david.holsgrove@xilinx.com>
Message-Id: <CAM=EW8aQDoNx-CkJHjXBoDP4iTDJ8z5hh3=KhO5UTU6rp3Pj=w@mail.gmail.com>
Patchwork-Id: 189053

Original patch from Gentoo.

-= BEGIN original header =-

-= END original header =-

diff -durN uClibc-0.9.30.orig/libc/inet/resolv.c uClibc-0.9.30/libc/inet/resolv.c

--- uClibc-0.9.30.orig/libc/inet/resolv.c	2008-11-02 01:25:33.000000000 +0100

+++ uClibc-0.9.30/libc/inet/resolv.c	2009-02-07 09:57:59.000000000 +0100

@@ -1788,7 +1788,7 @@

 int gethostent_r(struct hostent *result_buf, char *buf, size_t buflen,

 	struct hostent **result, int *h_errnop)

 {

-	int ret;

+	int ret = HOST_NOT_FOUND;

 	__UCLIBC_MUTEX_LOCK(mylock);

 	if (__gethostent_fp == NULL) {