Fix: re-enable compatibility with autoconf < 2.64

[urcu.git] / config / ax_tls.m4

diff --git a/config/ax_tls.m4 b/config/ax_tls.m4
index 033e3b135b8d6264e0b3151c3528ae7b3a74c6ca..5ab1a413d1414792e6b0098b7c13a42d56d9bdee 100644 (file)
--- a/config/ax_tls.m4
+++ b/config/ax_tls.m4
@@ -44,7 +44,23 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 10
+#serial 11
+
+#   Define m4_ifblank and m4_ifnblank macros from introduced in
+#   autotools 2.64 m4sugar.m4 if using an earlier autotools.
+
+ifdef([m4_ifblank], [], [
+m4_define([m4_ifblank],
+[m4_if(m4_translit([[$1]],  [ ][       ][
+]), [], [$2], [$3])])
+])
+
+
+ifdef([m4_ifnblank], [], [
+m4_define([m4_ifnblank],
+[m4_if(m4_translit([[$1]],  [ ][       ][
+]), [], [$3], [$2])])
+])
 
 AC_DEFUN([AX_TLS], [
   AC_MSG_CHECKING(for thread local storage (TLS) class)