diff --git a/stepmania/autoconf/m4/tls.m4 b/stepmania/autoconf/m4/tls.m4
new file mode 100644
index 0000000000..37bed15647
--- /dev/null
+++ b/stepmania/autoconf/m4/tls.m4
@@ -0,0 +1,14 @@
+# See if we have working TLS.  We only check to see if it compiles; we test
+# to see if it works at runtime, since we can run binaries compiled with __thread
+# on systems without TLS.
+AC_DEFUN(SM_TLS,
+[
+    AC_MSG_CHECKING(for TLS)
+    AC_TRY_COMPILE( [], [ static __thread int val; ], have_tls=yes,have_tls=no,have_tls=no )
+    AC_MSG_RESULT($have_tls)
+    if test "$have_tls" = "yes"; then
+        AC_DEFINE([HAVE_TLS],[1],[Define if the complier supports __thread])
+        AC_DEFINE([thread_local],[__thread],[Define to the compiler TLS keyword])
+    fi
+])
+