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>
(transplanted from 21f4f28e60ec0342133086c9a51e7f0e5b181fb8)

diff -durN glibc-cvs-2.9.orig/misc/syslog.c glibc-cvs-2.9/misc/syslog.c

--- glibc-cvs-2.9.orig/misc/syslog.c	2009-06-01 10:16:50.000000000 +0200

+++ glibc-cvs-2.9/misc/syslog.c	2009-06-01 10:17:20.000000000 +0200

@@ -152,7 +152,7 @@

 #define	INTERNALLOG	LOG_ERR|LOG_CONS|LOG_PERROR|LOG_PID

 	/* Check for invalid bits. */

 	if (pri & ~(LOG_PRIMASK|LOG_FACMASK)) {

-		syslog(INTERNALLOG,

+		__syslog(INTERNALLOG,

 		    "syslog: unknown facility/priority: %x", pri);

 		pri &= LOG_PRIMASK|LOG_FACMASK;

 	}