Pass CXXFLAGS to binutils/gold.

The GOLD linker is written in C++. Pass CT_CFLAGS_FOR_HOST as
CXXFLAGS to configure so that any host specific flags are passed
through.

It feels a bit funny passing CFLAGS as CXXFLAGS, but the PPL and GCC
target rules already do the same.

Signed-off-by: Michael Hope <michael.hope@linaro.org>

 #!/bin/sh

 # Needed for systems without gettext

 $* -xc -o /dev/null - > /dev/null 2>&1 << EOF

 #include <libintl.h>

 int main()

 {

 	gettext("");

 	return 0;

 }

 EOF

 if [ ! "$?" -eq "0"  ]; then

 	echo -DKBUILD_NO_NLS;

 fi