Override d/rules install to pass web root along

debian/rules

@@ -20,11 +20,14 @@ CARGO_REGISTRY=$(CURDIR)/debian/cargo_registry
 export DEB_CARGO_CRATE=$(DEB_SOURCE)_$(DEB_VERSION_UPSTREAM)
 export CFLAGS CXXFLAGS CPPFLAGS LDFLAGS
 
+WEBROOT=/usr/share/boids/
+export WEBROOT
+
 %:
 	dh $@
 
 execute_after_dh_auto_clean:
-	$(CARGO) clean
+# 	$(CARGO) clean
 	rm -rf $(CARGO_HOME)
 	rm -rf $(CARGO_REGISTRY)
 	rm -f debian/cargo-checksum.json
@@ -40,3 +43,6 @@ override_dh_auto_configure:
 override_dh_auto_test:
 # No tests. Can't execute a WASM binary
 	echo "Skipping tests, can't run WASM files"
+
+override_dh_auto_install:
+	dh_auto_install WEBROOT=$(WEBROOT)