diff -Nur gcc-6.1.0.orig/gcc/config.gcc gcc-6.1.0/gcc/config.gcc
--- gcc-6.1.0.orig/gcc/config.gcc	2016-04-11 12:14:59.000000000 +0200
+++ gcc-6.1.0/gcc/config.gcc	2016-06-18 13:36:12.196329752 +0200
@@ -833,6 +833,9 @@
 *-*-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*)