diff --git a/acinclude.m4 b/acinclude.m4
index 95a73e5ec..fcc2caf36 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1856,7 +1856,7 @@ AC_DEFUN([CURL_CHECK_FUNC_CLOCK_GETTIME_MONOTONIC], [
   AC_CHECK_HEADERS(sys/types.h sys/time.h time.h)
   AC_MSG_CHECKING([for monotonic clock_gettime])
   #
-  if test "x$dontwant_rt" == "xno" ; then
+  if test "x$dontwant_rt" = "xno" ; then
     AC_COMPILE_IFELSE([
       AC_LANG_PROGRAM([[
 #ifdef HAVE_SYS_TYPES_H