--- /usr/portage/eclass/apache-2.eclass	2012-05-23 05:31:13.000000000 +0200
+++ /usr/local/portage/eclass/apache-2.eclass	2012-07-26 12:53:23.449568498 +0200
@@ -69,8 +69,20 @@
 IUSE_MPMS="${IUSE_MPMS_FORK} ${IUSE_MPMS_THREAD}"
 IUSE="${IUSE} debug doc ldap selinux ssl static suexec threads"
 
+# @ECLASS-VARIABLE: MODULE_DEFAULTS
+# @DESCRIPTION:
+# This variable can be set in the ebuild and contains a space-separated
+# list of modules to be expanded to default flags according to IUSE-defaults.
+# Example:
+# IUSE_MODULES="foo" with MODULE_DEFAULTS="" => IUSE="apache2_modules_foo"
+# IUSE_MODULES="foo" with MODULE_DEFAULTS="foo" => IUSE="+apache2_modules_foo"
+
 for module in ${IUSE_MODULES} ; do
-	IUSE="${IUSE} apache2_modules_${module}"
+	if has ${module} ${MODULE_DEFAULTS} ; then
+		IUSE="${IUSE} +apache2_modules_${module}"
+	else
+		IUSE="${IUSE} apache2_modules_${module}"
+	fi
 done
 
 for mpm in ${IUSE_MPMS} ; do