update buildroot to 2017.02.11

bsp/buildroot-2017.02.11/package/gcc/4.9.4/940-uclinux-enable-threads.patch

@@ -0,0 +1,20 @@
+Enable POSIX threads for uClinux targets
+Reported upstream:
+https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71721
+
+Signed-off-by: Waldemar Brodkorb <wbx@openadk.org>
+
+Index: b/gcc/config.gcc
+===================================================================
+--- a/gcc/config.gcc
++++ b/gcc/config.gcc
+@@ -810,6 +810,9 @@
+ *-*-uclinux*)
+   extra_options="$extra_options gnu-user.opt"
+   use_gcc_stdint=wrap
++  case ${enable_threads} in
++    "" | yes | posix) thread_file='posix' ;;
++  esac
+   tm_defines="$tm_defines DEFAULT_LIBC=LIBC_UCLIBC SINGLE_LIBC"
+   ;;
+ *-*-rdos*)