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

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

MultiPart: 7/11

Change-Id: I252c4a40d5d4cb671c74b3d06027bab0b080aa17
diff --git a/client/Makefile b/client/Makefile
index 349ab62..c68a77d 100644
--- a/client/Makefile
+++ b/client/Makefile
@@ -1,4 +1,4 @@
-NODE_DIR := $(shell jiri v23-profile env --profile=nodejs V23_TARGET_INSTALLATION_DIR=)
+NODE_DIR := $(shell jiri v23-profile list --info Target.InstallationDir nodejs)
 PATH := bin:node_modules/.bin:$(PATH):$(NODE_DIR)/bin
 SHELL := /bin/bash -euo pipefail
 
diff --git a/go/src/v.io/x/playground/builder/builder_v23_test.go b/go/src/v.io/x/playground/builder/builder_v23_test.go
index 0d6de91..e0fafdb 100644
--- a/go/src/v.io/x/playground/builder/builder_v23_test.go
+++ b/go/src/v.io/x/playground/builder/builder_v23_test.go
@@ -31,7 +31,7 @@
 		i.Fatal("JIRI_ROOT must be set")
 	}
 
-	out, err := exec.Command("jiri", "v23-profile", "env", "--profile=nodejs", "V23_TARGET_INSTALLATION_DIR=").Output()
+	out, err := exec.Command("jiri", "v23-profile", "list", "--info=Target.InstallationDir", "nodejs").Output()
 	if err != nil {
 		i.Fatalf("could not find nodejs installation dir: %v", err)
 	}