-AC_PROG_CC_STDC
-
-# If not overridden, use ax_tls.m4 to check if TLS is available.
-AS_IF([test "x$def_compiler_tls" = "xyes"],
- [AX_TLS([def_tls_detect=$ac_cv_tls], [:])],
- [:])
-
-AS_IF([test "x$def_tls_detect" = "x"],
- [:],
- [AC_DEFINE_UNQUOTED([CONFIG_RCU_TLS], $def_tls_detect)])
+# AC_PROG_CC_STDC was merged in AC_PROG_CC in autoconf 2.70
+m4_version_prereq([2.70], [], [AC_PROG_CC_STDC])
+AS_IF([test "x$def_compiler_tls" = "xyes"], AC_DEFINE([CONFIG_RCU_TLS], [1]), [:])