Do not extract intel-ucode-with-caveats into the same directory as it needs
special handling.
Index: microcode_ctl-2.1-18/Makefile
===================================================================
--- microcode_ctl-2.1-18.orig/Makefile	2018-07-09 08:55:53.000000000 +0200
+++ microcode_ctl-2.1-18/Makefile	2018-07-20 17:52:34.767187807 +0200
@@ -21,8 +21,7 @@
 MICDIRINTEL     = $(MICDIR)/intel-ucode
 
 all:
-	tar xf $(MICROCODE_INTEL) ./intel-ucode/* ./intel-ucode-with-caveats/* \
-	       	--one-top-level=intel-ucode --strip-components=2 --backup=simple
+	tar -xf $(MICROCODE_INTEL) ./intel-ucode
 
 clean:
 	rm -rf intel-ucode