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 -dur strace-4.5.16.orig/syscall.c strace-4.5.16/syscall.c

--- strace-4.5.16.orig/syscall.c	2007-07-14 19:21:44.000000000 +0200

+++ strace-4.5.16/syscall.c	2007-07-14 19:22:49.000000000 +0200

@@ -125,6 +125,18 @@

 #define TP TRACE_PROCESS

 #define TS TRACE_SIGNAL

+#ifndef HAVE_STATFS64

+/*

+ * Ugly hacks for systems that do not have LFS

+ */

+

+#define sys_truncate64  sys_truncate

+#define sys_ftruncate64 sys_ftruncate

+#define sys_getdents64  sys_getdents

+#define sys_statfs64    sys_statfs

+#define sys_fstatfs64   sys_fstatfs

+#endif

+

 static const struct sysent sysent0[] = {

 #include "syscallent.h"

 };