Bump buidlroot version to 2018.02.6

bsp/buildroot/package/strace/Config.in

@@ -1,8 +1,14 @@
 config BR2_PACKAGE_STRACE
 	bool "strace"
+	# needs at least kernel headers 4.0 on nios2
+	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_0 || !BR2_nios2
 	help
 	  A useful diagnostic, instructional, and debugging tool.
 	  Allows you to track what system calls a program makes
 	  while it is running.
 
-	  http://sourceforge.net/projects/strace/
+	  https://strace.io
+
+comment "strace needs a toolchain w/ headers >= 4.0 on nios2"
+	depends on BR2_nios2
+	depends on !BR2_TOOLCHAIN_HEADERS_AT_LEAST_4_0

bsp/buildroot/package/strace/strace.hash

@@ -1,3 +1,7 @@
-# From https://sourceforge.net/projects/strace/files/strace/4.15/
-md5	1ff96209fec19914c920608ed0791864	strace-4.15.tar.xz
-sha1	18fbaeb07d089023764f618f179091b663a0d21e	strace-4.15.tar.xz
+# From https://sourceforge.net/projects/strace/files/strace/4.20/
+md5	f2271ab0fac49ebee9cbd7f3469227cb	strace-4.20.tar.xz
+sha1	9cebc754af3434e4027a07745770892f685c0316	strace-4.20.tar.xz
+# Locally calculated after checking signature
+# https://sourceforge.net/projects/strace/files/strace/4.20/strace-4.20.tar.xz.asc
+sha256	5bf3148dd17306a42566f7da17368fdd781afa147db05ea63a4ca2b50f58c523	strace-4.20.tar.xz
+sha256	ea7ff222f36c9df0aa2924a8f7c7d2aec3ea11e752feba4b15ec79b695b6236a	COPYING

bsp/buildroot/package/strace/strace.mk

@@ -4,10 +4,10 @@
 #
 ################################################################################
 
-STRACE_VERSION = 4.15
+STRACE_VERSION = 4.20
 STRACE_SOURCE = strace-$(STRACE_VERSION).tar.xz
 STRACE_SITE = http://downloads.sourceforge.net/project/strace/strace/$(STRACE_VERSION)
-STRACE_LICENSE = BSD-3c
+STRACE_LICENSE = BSD-3-Clause
 STRACE_LICENSE_FILES = COPYING
 
 # strace bundle some kernel headers to build libmpers, this mixes userspace