build: support make install "DESTDIR=/path"

Makefile

@@ -2,6 +2,7 @@
 
 BUILDTYPE ?= Release
 PYTHON ?= python
+DESTDIR ?=
 
 # BUILDTYPE=Debug builds both release and debug builds. If you want to compile
 # just the debug build, run `make -C out BUILDTYPE=Debug` instead.
@@ -33,7 +34,7 @@ out/Makefile: common.gypi deps/uv/uv.gyp deps/http_parser/http_parser.gyp deps/z
 	tools/gyp_node -f make
 
 install: all
-	out/Release/node tools/installer.js install
+	out/Release/node tools/installer.js install $(DESTDIR)
 
 uninstall:
 	out/Release/node tools/installer.js uninstall

tools/installer.js

@@ -1,7 +1,8 @@
 var fs = require('fs'),
     path = require('path'),
     exec = require('child_process').exec,
-    cmd = process.argv[2];
+    cmd = process.argv[2],
+    dest_dir = process.argv[3] || '';
 
 if (cmd !== 'install' && cmd !== 'uninstall') {
   console.error('Unknown command: ' + cmd);
@@ -26,7 +27,7 @@ function copy(src, dst, callback) {
     return;
   }
 
-  dst = path.join(node_prefix, dst);
+  dst = path.join(dest_dir, node_prefix, dst);
   var dir = dst.replace(/\/[^\/]*$/, '/');
 
   // Create directory if hasn't done this yet
@@ -42,7 +43,7 @@ function copy(src, dst, callback) {
 // Remove files
 function remove(files) {
   files.forEach(function(file) {
-    file = path.join(node_prefix, file);
+    file = path.join(dest_dir, node_prefix, file);
     queue.push('rm -rf ' + file);
   });
 }
@@ -127,9 +128,10 @@ if (cmd === 'install') {
   if (variables.node_install_npm) {
     copy('deps/npm', 'lib/node_modules/npm');
     queue.push('ln -sf ../lib/node_modules/npm/bin/npm-cli.js ' +
-               path.join(node_prefix, 'bin/npm'));
+               path.join(dest_dir, node_prefix, 'bin/npm'));
     queue.push([shebang, '#!' + path.join(node_prefix, 'bin/node'),
-               path.join(node_prefix, 'lib/node_modules/npm/bin/npm-cli.js')]);
+               path.join(dest_dir, node_prefix,
+                         'lib/node_modules/npm/bin/npm-cli.js')]);
   }
 } else {
   remove([