* enable.m4: New file.

	* tls.m4: New file.

1 files changed, 21 insertions, 0 deletions

diff --git a/config/tls.m4 b/config/tls.m4
new file mode 100644
index 00000000000..5cbb6854f6c
--- /dev/null
+++ b/config/tls.m4
@@ -0,0 +1,21 @@
+dnl Check whether the target supports TLS.
+AC_DEFUN([GCC_CHECK_TLS], [
+  GCC_ENABLE(tls, yes, [Use thread-local storage])
+  AC_CACHE_CHECK([whether the target supports thread-local storage],
+		 have_tls, [
+    AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
+      [dnl If the test case passed with dynamic linking, try again with
+      dnl static linking.  This fails at least with some older Red Hat
+      dnl releases.
+      save_LDFLAGS="$LDFLAGS"
+      LDFLAGS="-static $LDFLAGS"
+      AC_RUN_IFELSE([__thread int a; int b; int main() { return a = b; }],
+		    [have_tls=yes], [have_tls=no], [])
+      LDFLAGS="$save_LDFLAGS"],
+      [have_tls=no],
+      [AC_COMPILE_IFELSE([__thread int foo;], [have_tls=yes], [have_tls=no])]
+    )])
+  if test "$enable_tls $have_tls" = "yes yes"; then
+    AC_DEFINE(HAVE_TLS, 1,
+	      [Define to 1 if the target supports thread-local storage.])
+  fi])