Bump buidlroot version to 2018.02.6

bsp/buildroot/package/libressl/0001-remove-test-z-DESTDIR-from-ltmain.patch

@@ -0,0 +1,28 @@
+From 4317d43d74996ad7ec3270b1e786e91a19312309 Mon Sep 17 00:00:00 2001
+From: Adam Duskett <Adamduskett@outlook.com>
+Date: Sat, 24 Jun 2017 13:08:57 -0400
+Subject: [PATCH] remove test -z "$DESTDIR" from ltmain.sh.
+
+Without this patch, buildroot-libtool-v2.4.patch will fail to apply.
+
+Signed-off-by: Adam Duskett <Adamduskett@outlook.com>
+---
+ ltmain.sh | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/ltmain.sh b/ltmain.sh
+index 5d29bd6..6c90601 100644
+--- a/ltmain.sh
++++ b/ltmain.sh
+@@ -6658,7 +6658,7 @@ func_mode_link ()
+ 	  *)
+ 	    if test "$installed" = no; then
+ 	      func_append notinst_deplibs " $lib"
+-	      test -z "$DESTDIR" && need_relink=yes
++	      need_relink=yes
+ 	    fi
+ 	    ;;
+ 	  esac
+-- 
+2.9.4
+