Termux is effectively a single-user system so chown:ing
does not make much sense.

Without this patch npm fails with EPERM on chown
for cache.json when first building the local index.
diff -u -r ../node-v0.12.7/deps/npm/lib/cache/update-index.js ./deps/npm/lib/cache/update-index.js
--- ../node-v0.12.7/deps/npm/lib/cache/update-index.js	2015-07-09 18:41:19.000000000 -0400
+++ ./deps/npm/lib/cache/update-index.js	2015-07-24 20:45:21.078116384 -0400
@@ -4,7 +4,7 @@
 var assert = require('assert')
 var path = require('path')
 var mkdir = require('mkdirp')
-var chownr = require('chownr')
+var chownr = function(path, uid, gid, cb) { cb(null); }
 var npm = require('../npm.js')
 var log = require('npmlog')
 var cacheFile = require('npm-cache-filename')