diff --git a/Makefile.builder b/Makefile.builder
index 4a2170e..db4cd27 100644
--- a/Makefile.builder
+++ b/Makefile.builder
@@ -1,13 +1,13 @@
-ifeq ($(PACKAGE_SET),dom0)
-RPM_SPEC_FILES := \
-	anaconda/anaconda.spec \
-	firstboot/firstboot.spec \
-	qubes-release/qubes-release.spec \
-	lorax/lorax.spec \
-	lorax-templates-qubes/lorax-templates-qubes.spec \
-	pungi/pungi.spec \
-	pykickstart/pykickstart.spec \
-	qubes-release/qubes-dom0-dist-upgrade.spec \
+RPM_SPEC_FILES.dom0 := \
+    pykickstart/pykickstart.spec \
+    lorax/lorax.spec \
+    lorax-templates-qubes/lorax-templates-qubes.spec \
+    pungi/pungi.spec \
+    anaconda/anaconda.spec \
+    firstboot/firstboot.spec \
+    qubes-release/qubes-release.spec \
+    qubes-release/qubes-dom0-dist-upgrade.spec \
     livecd-tools/livecd-tools.spec \
     live/qubes-live.spec
-endif
+
+RPM_SPEC_FILES := $(RPM_SPEC_FILES.$(PACKAGE_SET))