-build_subdirs := ir/adt ir/debug ir/tv ir/common ir/ident ir/ir ir/opt ir/tr ir/ana \
- ir/stat ir/external ir/ana2
+# suck in values for the linking procedure:
+LDFLAGS = @LDFLAGS@
+LIBS = @LIBS@
+
+# plugin subdirectories
+plugin_subdirs := @plugin_subdirs@
+
+build_subdirs := ir/adt ir/debug ir/tv ir/common ir/ident ir/ir \
+ ir/opt ir/tr ir/ana ir/stat ir/ana2 ir/arch \
+ $(plugin_subdirs)
+
+ifeq (@enable_external_effects@,yes)
+build_subdirs += ir/external
+endif