Add support for Xcode LastUpgradeCheck project attributes, allowing

pylib/gyp/generator/xcode.py

Index: pylib/gyp/generator/xcode.py
diff --git a/pylib/gyp/generator/xcode.py b/pylib/gyp/generator/xcode.py
index 482b53ac8ad9ecf4c8a45db0f2095a30ceb77fb7..119a631d5ae54f466f0d83ac6a17ee9f162fb352 100644
--- a/pylib/gyp/generator/xcode.py
+++ b/pylib/gyp/generator/xcode.py
@@ -590,6 +590,16 @@ def GenerateOutput(target_list, target_dicts, data, params):
   parallel_builds = generator_flags.get('xcode_parallel_builds', True)
   serialize_all_tests = \
       generator_flags.get('xcode_serialize_all_test_runs', True)
+  project_version = generator_flags.get('xcode_project_version', None)
+  upgrade_check_project_version = \

[Mark Mentovai, 2015/10/21 00:34:25]

= int(generator_flags.get(…))

to make sure that it’s an int, since the 0-appending thing you do kind of
assumes that it’s a number.

[aharper, 2015/10/21 00:39:19]

So the int conversion actually happens in gyp/__init__.py NameValueListToDict().
I actually wanted to suppress that conversion because it eats the leading zero 
but seemed more risky. So this code assumes only that we have a value that can
stringify (line 599) and that we need to pad to 4 chars.

+      generator_flags.get('xcode_upgrade_check_project_version', None)
+
+  # Format upgrade_check_project_version with leading zeros as needed.
+  if upgrade_check_project_version:
+    upgrade_check_project_version = str(upgrade_check_project_version)
+    while len(upgrade_check_project_version) < 4:
+      upgrade_check_project_version = '0' + upgrade_check_project_version
+
   skip_excluded_files = \
       not generator_flags.get('xcode_list_excluded_files', True)
   xcode_projects = {}
@@ -604,9 +614,18 @@ def GenerateOutput(target_list, target_dicts, data, params):
     xcode_projects[build_file] = xcp
     pbxp = xcp.project
 
+    # Set project-level attributes from multiple options
+    project_attributes = {};
     if parallel_builds:
-      pbxp.SetProperty('attributes',
-                       {'BuildIndependentTargetsInParallel': 'YES'})
+      project_attributes['BuildIndependentTargetsInParallel'] = 'YES'
+    if upgrade_check_project_version:
+      project_attributes['LastUpgradeCheck'] = upgrade_check_project_version
+      project_attributes['LastTestingUpgradeCheck'] = \
+          upgrade_check_project_version
+    pbxp.SetProperty('attributes', project_attributes)
+
+    if project_version:
+      xcp.project_file.SetXcodeVersion(project_version)
 
     # Add gyp/gypi files to project
     if not generator_flags.get('standalone'):