Added support of the PlatformToolset property to Gyp (MSBuild only).

pylib/gyp/generator/msvs.py

Index: pylib/gyp/generator/msvs.py
diff --git a/pylib/gyp/generator/msvs.py b/pylib/gyp/generator/msvs.py
index a4c6efd1a466c97afbffd00938fb8e63a0727dfa..ab814c7794cc54037c40f588126c7b84afce696f 100644
--- a/pylib/gyp/generator/msvs.py
+++ b/pylib/gyp/generator/msvs.py
@@ -1661,6 +1661,11 @@ def CalculateVariables(default_variables, params):
   # Set a variable so conditions can be based on msvs_version.
   default_variables['MSVS_VERSION'] = msvs_version.ShortName()
 
+  # Use the platform toolset specified in the environment (MSBuild only)
+  msvs_toolset = generator_flags.get(
+      'msvs_toolset', os.environ.get('GYP_MSVS_TOOLSET', 'auto'))
+  generator_flags['msvs_toolset'] = msvs_toolset
+
   # To determine processor word size on Windows, in addition to checking
   # PROCESSOR_ARCHITECTURE (which reflects the word size of the current
   # process), it is also necessary to check PROCESSOR_ARCITEW6432 (which
@@ -2834,6 +2839,15 @@ def _GenerateMSBuildProject(project, options, version, generator_flags):
   content += _GetMSBuildGlobalProperties(spec, project.guid, project_file_name)
   content += import_default_section
   content += _GetMSBuildConfigurationDetails(spec, project.build_file)
+
+  # Specify a platform toolset for the project if set.
+  msvs_toolset = generator_flags.get('msvs_toolset', 'auto')

[bradn, 2012/02/15 06:23:17]

Rather than having this be a generator flag, could we base it on something in
spec/configuration? So it can be configured in common.gypi ? That way everyone
doesn't need to tweak their environment. If its set via a gyp variable with % it
can still be overridden as needed.

Little rusty on the scheme, I realize msbuild_settings clobbers msvs_settings,
so we probably can't add it to msbuild_settings?

[alexeypa (please no reviews), 2012/02/17 18:11:40]

This certainly makes sense. Take a look at the updated CL.

+  if msvs_toolset != 'auto':
+    content += [
+        ['PropertyGroup', {'Label': 'Locals'},
+         ['PlatformToolset', msvs_toolset],
+        ]]
+
   content += import_cpp_props_section
   content += _GetMSBuildExtensions(props_files_of_rules)
   content += _GetMSBuildPropertySheets(configurations)