v.io/jiri: add policy driven flags for merging environment variables.

- Also tidy up v23-profile env, list etc.

MultiPart: 6/11

Change-Id: If25106cd84ec1faeb5fc71957a6f831fa6a3a4de
diff --git a/Makefile b/Makefile
index 6a48e91..945dd3e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-NODE_DIR := $(shell jiri v23-profile env --profile=nodejs V23_TARGET_INSTALLATION_DIR=)
+NODE_DIR := $(shell jiri v23-profile list --info Target.InstallationDir nodejs)
 export PATH:=$(NODE_DIR)/bin:$(CURDIR)/node_modules/.bin:$(PATH)
 export GOPATH=$(CURDIR)/go
 export VDLPATH=$(GOPATH)