+app-dirs =
+tagged-app-dirs := $(subst /,__,$(app-dirs))
+app-dirs-install := $(addprefix _install_,$(tagged-app-dirs))
+app-dirs-clean := $(addprefix _clean_,$(tagged-app-dirs))
+
+PHONY += $(app-dirs-install) $(app-dirs-clean)
+
+$(app-dirs-install):
+ @$(MAKE) -C $(patsubst _install_%,%,$(subst __,/,$@)) install
+
+$(app-dirs-clean):
+ @$(MAKE) -C $(patsubst _clean_%,%,$(subst __,/,$@)) clean
+
+PHONY += apps-install
+apps-install: $(app-dirs-install)