diff --git a/Makefile.coq.local b/Makefile.coq.local
index 67a468e4efe0418f55205e1545ad48e07ae461bf..12e6f7829a6ce682ae83ee160a05d72449e45bea 100644
--- a/Makefile.coq.local
+++ b/Makefile.coq.local
@@ -21,7 +21,8 @@ test: $(TESTFILES:.v=.vo)
 .PHONY: test
 
 COQ_TEST=$(COQTOP) $(COQDEBUG) -batch -test-mode
-COQ_MINOR_VERSION:=$(shell echo "$(COQ_VERSION)" | egrep '^[0-9]+\.[0-9]+\b' -o)
+# Need to make this a lazy variable (`=` instead of `:=`) since COQ_VERSION is only set later.
+COQ_MINOR_VERSION=$(shell echo "$(COQ_VERSION)" | egrep '^[0-9]+\.[0-9]+\b' -o)
 
 tests/.coqdeps.d: $(TESTFILES)
 	$(SHOW)'COQDEP TESTFILES'