diff --git a/configure.ac b/configure.ac
index cb552ea94f..5fbf22bd11 100644
--- a/configure.ac
+++ b/configure.ac
@@ -439,7 +439,7 @@ AC_CACHE_CHECK([for __attribute__((fallthrough))],
 	 [tor_cv_c_attr_fallthrough=no] )])
 CFLAGS="$saved_CFLAGS"
 
-if test "$tor_cv_c_attr_fallthrough" == "yes"; then
+if test "$tor_cv_c_attr_fallthrough" = "yes"; then
   AC_DEFINE(HAVE_ATTR_FALLTHROUGH, [1], [defined if we have the fallthrough attribute.])
 fi