Bump buildroot to 2019.02

bsp/buildroot/support/dependencies/check-host-gzip.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+candidate="$1" # ignored
+
+gzip="$(which gzip)"
+if [ ! -x "${gzip}" ]; then
+    # echo nothing: no suitable gzip found
+    exit 1
+fi
+
+# gzip displays its version string on stdout
+# pigz displays its version string on stderr
+version="$("${gzip}" --version 2>&1)"
+case "${version}" in
+  (*pigz*)
+    # echo nothing: no suitable gzip found
+    exit 1
+    ;;
+esac
+
+printf "%s" "${gzip}"