scripts: unset CONFIG_SITE

Some distributions (eg. openSUSE 12.1) systematically export
the CONFIG_SITE environment variable to point to a custom
script setting misc paths for ./configure.

This can, and does, break when cross-compiling for architectures
that are not supported by this script.

The simple workaround is to unset this variable.
NB: buildroot has a similar fix:
http://git.buildroot.org/buildroot/commit/?id=12c9f7dd6dee9c6029b4f9a12d6aac1516911ab4

Reported-by: Trevor Woerner <twoerner@gmail.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

Enable building a pure soft-float compiler without the need for a software

floating point library.

diff -dur gcc-4.0.4.orig/gcc/config.gcc gcc-4.0.4/gcc/config.gcc

--- gcc-4.0.4.orig/gcc/config.gcc	2007-02-02 19:12:28.000000000 +0100

+++ gcc-4.0.4/gcc/config.gcc	2007-02-02 19:12:07.000000000 +0100

@@ -677,7 +677,7 @@

 		tm_defines="TARGET_BIG_ENDIAN_DEFAULT=1 $tm_defines"

 		;;

 	esac

-	tmake_file="${tmake_file} arm/t-arm arm/t-linux"

+	tmake_file="${tmake_file} arm/t-arm arm/t-linux arm/t-arm-elf"

 	extra_parts="crtbegin.o crtbeginS.o crtend.o crtendS.o"

 	gnu_ld=yes

 	;;