Add support for "else if" in gyp conditions

test/conditions/elseif/elseif.gyp

Index: test/conditions/elseif/elseif.gyp
diff --git a/test/conditions/elseif/elseif.gyp b/test/conditions/elseif/elseif.gyp
new file mode 100644
index 0000000000000000000000000000000000000000..6367ff7d7afef580e47d50e4ff8f632106c196f1
--- /dev/null
+++ b/test/conditions/elseif/elseif.gyp
@@ -0,0 +1,43 @@
+# Copyright (c) 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'targets': [
+    {
+      'variables': { 'test_var': 0 },
+      'target_name': 'program0',
+      'type': 'executable',
+      'sources': [ 'program.cc' ],
+      'includes': [ 'elseif_conditions.gypi' ],
+    },
+    {
+      'variables': { 'test_var': 1 },
+      'target_name': 'program1',
+      'type': 'executable',
+      'sources': [ 'program.cc' ],
+      'includes': [ 'elseif_conditions.gypi' ],
+    },
+    {
+      'variables': { 'test_var': 2 },
+      'target_name': 'program2',
+      'type': 'executable',
+      'sources': [ 'program.cc' ],
+      'includes': [ 'elseif_conditions.gypi' ],
+    },
+    {
+      'variables': { 'test_var': 3 },
+      'target_name': 'program3',
+      'type': 'executable',
+      'sources': [ 'program.cc' ],
+      'includes': [ 'elseif_conditions.gypi' ],
+    },
+    {
+      'variables': { 'test_var': 4 },
+      'target_name': 'program4',
+      'type': 'executable',
+      'sources': [ 'program.cc' ],
+      'includes': [ 'elseif_conditions.gypi' ],
+    },
+  ],
+}