xcode: add new package ID for Mavericks.

Closes Homebrew/homebrew#30296.

Library/Homebrew/os/mac/xcode.rb

@@ -146,7 +146,8 @@ module OS
 
       STANDALONE_PKG_ID = "com.apple.pkg.DeveloperToolsCLILeo"
       FROM_XCODE_PKG_ID = "com.apple.pkg.DeveloperToolsCLI"
-      MAVERICKS_PKG_ID = "com.apple.pkg.CLTools_Executables"
+      MAVERICKS_PKG_IDS = ["com.apple.pkg.CLTools_Base",
+                           "com.apple.pkg.CLTools_Executables"]
       MAVERICKS_PKG_PATH = "/Library/Developer/CommandLineTools"
 
       # Returns true even if outdated tools are installed, e.g.
@@ -181,7 +182,7 @@ module OS
       end
 
       def detect_version
-        [MAVERICKS_PKG_ID, STANDALONE_PKG_ID, FROM_XCODE_PKG_ID].find do |id|
+        [*MAVERICKS_PKG_IDS, STANDALONE_PKG_ID, FROM_XCODE_PKG_ID].find do |id|
           version = MacOS.pkgutil_info(id)[/version: (.+)$/, 1]
           return version if version
         end