Cross-compilation check broken

[Pavel Roskin <proski@gnu.org>]

Hello, Robert!

Your commit 1955 breaks my script for testing PowerPC.  That's the
script:

#!/bin/sh
set -e
CROSS_PATH=/home/proski/src/buildroot/build_powerpc/staging_dir/usr/bin
PATH=$CROSS_PATH:$PATH
./configure --with-platform=ieee1275 --target=powerpc-linux
make -j2
./grub-mkrescue --grub-mkimage=./grub-mkelfimage --pkglibdir=. grub.iso
qemu-system-ppc -nographic -cdrom grub.iso -boot d

I compile for target "powerpc-linux" and I have powerpc-linux-gcc in the
PATH.  However, I'm using native tools.  I'm not interested in running
tools in an emulator (actually, I have another script that does it).
Therefore, build and host are the same, so TARGET_CC is set to gcc.

The new check must be wrong.  TARGET_CC is used to build executables for
the target system.  It should be found using the specified target even
if the tools are compiled natively.

Actually, the original check wasn't particularly good.  Maybe we could
check if target_alias is defined?  Or maybe we could always check for
TARGET_CC?

-- 
Regards,
Pavel Roskin