diff --git a/configure.ac b/configure.ac
index f103b3bfb..2a3d35da4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -176,6 +176,7 @@ if test "$GCC" = "yes" || test "$GCC" = "egcs"; then
 	OSSH_CHECK_CFLAG_COMPILE([-Wunused-parameter], [-Wno-unused-parameter])
 	OSSH_CHECK_CFLAG_COMPILE([-Wunused-result], [-Wno-unused-result])
 	OSSH_CHECK_CFLAG_COMPILE([-Wimplicit-fallthrough])
+	OSSH_CHECK_CFLAG_COMPILE([-Wmisleading-indentation])
 	OSSH_CHECK_CFLAG_COMPILE([-fno-strict-aliasing])
     if test "x$use_toolchain_hardening" = "x1"; then
 	OSSH_CHECK_CFLAG_COMPILE([-mretpoline]) # clang