--- old/src/Makefile.spack
+++ new/src/Makefile.spack
@@ -0,0 +1,20 @@
+# Set PREFIX to the install location for both building and installing
+
+all: valid xporta
+
+valid: common.lo arith.lo inout.lo log.lo valid.lo
+	libtool --mode=link --tag=CC cc -g -O3 -o $@ $^
+
+xporta: common.lo arith.lo inout.lo log.lo				\
+		porta.lo four_mot.lo portsort.lo largecalc.lo mp.lo
+	libtool --mode=link --tag=CC cc -g -O3 -o $@ $^
+
+%.lo: %.c
+	libtool --mode=compile --tag=CC cc -g -O3 -c $*.c
+
+install:
+	mkdir -p $(PREFIX)/bin
+	libtool --mode=install cp valid $(PREFIX)/bin/valid
+	libtool --mode=install cp xporta $(PREFIX)/bin/xporta
+
+.PHONY: all install