Bump buidlroot version to 2018.02.6

bsp/buildroot/package/openntpd/0001-fix-musl.patch

@@ -0,0 +1,38 @@
+From: Baruch Siach <baruch@tkos.co.il>
+Date: Fri, 29 Sep 2017 10:06:52 +0300
+Subject: [PATCH] Fix build with musl and older Linux kernel
+
+The musl libc carries its own copy of Linux system calls. When building
+with Linux headers older than v3.17, musl provides SYS_getrandom
+definition, but not GRND_NONBLOCK. This causes build failure for
+libressl and openntpd:
+
+getentropy_linux.c: In function 'getentropy_getrandom':
+getentropy_linux.c:205:42: error: 'GRND_NONBLOCK' undeclared (first use in this function)
+   ret = syscall(SYS_getrandom, buf, len, GRND_NONBLOCK);
+                                          ^~~~~~~~~~~~~
+
+Define GRND_NONBLOCK locally when its definition is missing to fix the
+build. There should be no run-time effect. Older kernels return ENOSYS
+for unsupported syscall().
+
+[ from upstream pull request with file location changed ]
+Signed-off-by: Baruch Siach <baruch@tkos.co.il>
+---
+Upstream status: https://github.com/libressl-portable/openbsd/pull/82
+
+diff -Nuar openntpd-6.2p2-orig/compat/getentropy_linux.c openntpd-6.2p2/compat/getentropy_linux.c
+--- openntpd-6.2p2-orig/compat/getentropy_linux.c	2017-09-07 22:12:02.000000000 +0300
++++ openntpd-6.2p2/compat/getentropy_linux.c	2017-09-29 11:54:54.856245770 +0300
+@@ -194,6 +194,11 @@
+ }
+ 
+ #ifdef SYS_getrandom
++
++#ifndef GRND_NONBLOCK
++#define GRND_NONBLOCK   0x0001
++#endif
++
+ static int
+ getentropy_getrandom(void *buf, size_t len)
+ {