Add a bootstrapping Makefile (from iris-coq)

.gitignore

@@ -12,5 +12,4 @@
 *~
 *.bak
 .coq-native/
-Makefile
-Makefile.coq
\ No newline at end of file
+Makefile.coq

Makefile

+#####
+## This has been adapted from the Makefile of iris-coq
+
+# Forward most targets to Coq makefile (with some trick to make this phony)
+%: Makefile.coq phony
+	+@make -f Makefile.coq $@
+
+all: Makefile.coq
+	+@make -f Makefile.coq all
+
+clean: Makefile.coq
+	+@make -f Makefile.coq clean
+	find theories \( -name "*.v.d" -o -name "*.vo" -o -name "*.aux" -o -name "*.cache" -o -name "*.glob" -o -name "*.vio" \) -print -delete
+	rm -f Makefile.coq
+
+Makefile.coq: _CoqProject Makefile awk.Makefile
+	coq_makefile -f _CoqProject -o Makefile.coq
+
+# Some files that do *not* need to be forwarded to Makefile.coq
+Makefile: ;
+_CoqProject: ;
+awk.Makefile: ;
+
+# Phony targets (i.e. targets that should be run no matter the timestamps of the involved files)
+phony: ;
+.PHONY: all clean phony