Revised the build system so that all packages that are to be automatically
downloaded and installed are done during "make" instead of during
"configure".  This includes moving URLs into the Makefile, moving actions
like untarring into the download script, and replacing the "information"
file for the PDK with a custom download script.
diff --git a/Makefile.in b/Makefile.in
index b0fcdc0..a4e8a02 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -67,6 +67,7 @@
 	@echo $(DONE_MESSAGE)
 
 distclean: $(TECHS_VERYCLEAN)
+	${RM} -rf sources
 	@echo $(DONE_MESSAGE)
 
 #---------------------------------------------------
@@ -85,4 +86,4 @@
 veryclean-sky130:
 	(cd sky130 && ${MAKE} veryclean)
 
-#---------------------------------------------------
\ No newline at end of file
+#---------------------------------------------------