node: doesn't require Xcode

This reverts commit 10e219d.

Multiple users have reported that node builds just fine with a CLT-only
system, and provided build logs to show it. Restoring CLT-only support
until a build failure is demonstrated again by another user.

Library/Formula/node.rb

@@ -59,16 +59,18 @@ class Node < Formula
   depends_on PythonVersion
   depends_on 'v8' if build.with? 'shared-libs'
 
-  # gyp insists on using xcodebuild to find the SDK path, completely
-  # breaking CLT-only systems.
-  # See: https://code.google.com/p/gyp/issues/detail?id=292
-  depends_on :xcode
-
   fails_with :llvm do
     build 2326
   end
 
   def install
+    # Lie to `xcode-select` for now to work around a GYP bug that affects
+    # CLT-only systems:
+    #
+    #   http://code.google.com/p/gyp/issues/detail?id=292
+    #   joyent/node#3681
+    ENV['DEVELOPER_DIR'] = MacOS.dev_tools_path unless MacOS::Xcode.installed?
+
     args = %W{--prefix=#{prefix}}
 
     if build.with? 'shared-libs'