Allow build directory to be changed.

Change with `--build-dir` parameter.

ie:
```
node-gyp --build-dir=foo rebuild
```

PR nodejs#919
Fixes nodejs#263

bin/node-gyp.js

@@ -22,6 +22,7 @@ var path = require('path')
 var prog = gyp()
 var completed = false
 prog.parseArgv(process.argv)
+prog.buildDir = prog.opts['build-dir'] || 'build'
 prog.devDir = prog.opts.devdir
 
 var homeDir = osenv.home()

lib/build.js

@@ -29,7 +29,7 @@ function build (gyp, argv, callback) {
   var release = processRelease(argv, gyp, process.version, process.release)
     , makeCommand = gyp.opts.make || process.env.MAKE || platformMake
     , command = win ? 'msbuild' : makeCommand
-    , buildDir = path.resolve('build')
+    , buildDir = path.resolve(gyp.buildDir)
     , configPath = path.resolve(buildDir, 'config.gypi')
     , jobs = gyp.opts.jobs || process.env.JOBS
     , buildType
@@ -86,7 +86,7 @@ function build (gyp, argv, callback) {
    */
 
   function findSolutionFile () {
-    glob('build/*.sln', function (err, files) {
+    glob(buildDir + '/*.sln', function (err, files) {
       if (err) return callback(err)
       if (files.length === 0) {
         return callback(new Error('Could not find *.sln file. Did you run "configure"?'))
@@ -240,7 +240,7 @@ function build (gyp, argv, callback) {
       argv.push('BUILDTYPE=' + buildType)
       // Invoke the Makefile in the 'build' dir.
       argv.push('-C')
-      argv.push('build')
+      argv.push(buildDir)
       if (jobs) {
         var j = parseInt(jobs, 10)
         if (!isNaN(j) && j > 0) {

lib/clean.js

@@ -14,7 +14,7 @@ var log = require('npmlog')
 function clean (gyp, argv, callback) {
 
   // Remove the 'build' dir
-  var buildDir = 'build'
+  var buildDir = gyp.buildDir
 
   log.verbose('clean', 'removing "%s" directory', buildDir)
   rm(buildDir, callback)

lib/configure.js

@@ -28,7 +28,7 @@ exports.usage = 'Generates ' + (win ? 'MSVC project files' : 'a Makefile') + ' f
 function configure (gyp, argv, callback) {
 
   var python = gyp.opts.python || process.env.PYTHON || 'python2'
-    , buildDir = path.resolve('build')
+    , buildDir = path.resolve(gyp.buildDir)
     , configNames = [ 'config.gypi', 'common.gypi' ]
     , configs = []
     , nodeDir
@@ -154,12 +154,13 @@ function configure (gyp, argv, callback) {
       return v
     }
 
-    log.silly('build/' + configFilename, config)
+    log.silly(gyp.buildDir + '/' + configFilename, config)
 
     // now write out the config.gypi file to the build/ dir
     var prefix = '# Do not edit. File was generated by node-gyp\'s "configure" step'
       , json = JSON.stringify(config, boolsToString, 2)
-    log.verbose('build/' + configFilename, 'writing out config file: %s', configPath)
+    log.verbose(gyp.buildDir + '/' + configFilename,
+                'writing out config file: %s', configPath)
     configs.push(configPath)
     fs.writeFile(configPath, [prefix, json, ''].join('\n'), findConfigs)
   }
@@ -254,7 +255,7 @@ function configure (gyp, argv, callback) {
       if (err)
         common_gypi = path.resolve(nodeDir, 'common.gypi')
 
-      var output_dir = 'build'
+      var output_dir = gyp.buildDir
       if (win) {
         // Windows expects an absolute path
         output_dir = buildDir

lib/node-gyp.js

@@ -48,6 +48,7 @@ function Gyp () {
 
   this.devDir = ''
   this.commands = {}
+  this.buildDir = ''
 
   commands.forEach(function (command) {
     self.commands[command] = function (argv, callback) {
@@ -89,6 +90,7 @@ proto.configDefs = {
   , 'tarball': String // 'install'
   , jobs: String      // 'build'
   , thin: String      // 'configure'
+  , 'build-dir': String // everywhere
 }
 
 /**

test/test-addon.js

@@ -1,7 +1,9 @@
 'use strict'
 
 var test = require('tape')
-var execFile = require('child_process').execFile
+var childProcess = require('child_process')
+var execFile = childProcess.execFile
+var exec = childProcess.exec
 var path = require('path')
 var addonPath = path.resolve(__dirname, 'node_modules', 'hello_world')
 var nodeGyp = path.resolve(__dirname, '..', 'bin', 'node-gyp.js')
@@ -26,3 +28,27 @@ test('build simple addon', function (t) {
   proc.stdout.setEncoding('utf-8')
   proc.stderr.setEncoding('utf-8')
 })
+
+test('build with different build dir', function(t) {
+  var cmd = [nodeGyp, 'rebuild', '-C',
+              addonPath, '--loglevel=verbose', '--build-dir=foo']
+  var proc = execFile(process.execPath, cmd, function (err, stdout, stderr) {
+    var logLines = stderr.toString().trim().split(/\r?\n/)
+    var lastLine = logLines[logLines.length-1]
+    t.strictEqual(err, null)
+    t.strictEqual(lastLine, 'gyp info ok', 'should end in ok')
+
+    try {
+      var binding = require('hello_world')
+      t.strictEqual(binding.hello(), 'world')
+
+      // Cleanup
+      exec('node-gyp --build-dir=foo clean', t.end)
+    } catch (error) {
+      t.error(error, 'load module')
+    }
+  })
+
+  proc.stdout.setEncoding('utf-8')
+  proc.stderr.setEncoding('utf-8')
+})