diff --git a/rpm_spec/core-libs.spec b/rpm_spec/core-libs.spec
index a2931bf..00c3582 100644
--- a/rpm_spec/core-libs.spec
+++ b/rpm_spec/core-libs.spec
@@ -42,9 +42,16 @@ BuildRequires: xen-devel
 %description
 The Qubes core libraries for installation inside a Qubes Dom0 and VM.
 
+%prep
+# we operate on the current directory, so no need to unpack anything
+# symlink is to generate useful debuginfo packages
+rm -f %{name}-%{version}
+ln -sf . %{name}-%{version}
+%setup -T -D
+
 %build
-make -C u2mfn
-make -C vchan -f Makefile.linux
+(cd u2mfn; make)
+(cd vchan; make -f Makefile.linux)
 
 %install
 install -D -m 0644 vchan/libvchan.h $RPM_BUILD_ROOT/usr/include/libvchan.h
@@ -54,6 +61,10 @@ install -D -m 0644 u2mfn/u2mfn-kernel.h $RPM_BUILD_ROOT/usr/include/u2mfn-kernel
 install -D vchan/libvchan.so $RPM_BUILD_ROOT/%{_libdir}/libvchan.so
 install -D u2mfn/libu2mfn.so $RPM_BUILD_ROOT/%{_libdir}/libu2mfn.so
 
+%clean
+rm -rf $RPM_BUILD_ROOT
+rm -f %{name}-%{version}
+
 %files
 %{_libdir}/libvchan.so
 %{_libdir}/libu2mfn.so
diff --git a/rpm_spec/core-vm.spec b/rpm_spec/core-vm.spec
index 0e4e17e..8bc7be0 100644
--- a/rpm_spec/core-vm.spec
+++ b/rpm_spec/core-vm.spec
@@ -56,12 +56,19 @@ BuildRequires: xen-devel
 %description
 The Qubes core files for installation inside a Qubes VM.
 
+%prep
+# we operate on the current directory, so no need to unpack anything
+# symlink is to generate useful debuginfo packages
+rm -f %{name}-%{version}
+ln -sf . %{name}-%{version}
+%setup -T -D
+
 %build
-make -C u2mfn
-make -C vchan -f Makefile.linux
-make -C misc
-make -C qubes_rpc
-make -C qrexec
+(cd vchan; make -f Makefile.linux)
+(cd qrexec; make)
+for dir in qubes_rpc misc; do
+  (cd $dir; make)
+done
 
 %pre
 
@@ -358,6 +365,7 @@ fi
 
 %clean
 rm -rf $RPM_BUILD_ROOT
+rm -f %{name}-%{version}
 
 %files
 %defattr(-,root,root,-)