diff --git a/configure.ac b/configure.ac
index e4c6aaec..03883ad7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -682,7 +682,7 @@ if test "$enable_utmpx" = "yes"; then
 	          [Define if utmpx should be used])
 fi
 
-AC_DEFINE_UNQUOTED(SHELL, ["$SHELL"], [The default shell.])
+AC_DEFINE_UNQUOTED(SHELL, ["$RUNTIME_SHELL"], [The runtime shell.])
 
 AM_GNU_GETTEXT_VERSION(0.16)
 AM_GNU_GETTEXT([external], [need-ngettext])