msvs: Prefer x64 toolset if we are running on 64-bit

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 35021dc4be333308699a16784950a807789167d8..f8a19a23cc9264c61688efaaacf9884437c22e5e 100644
--- a/pylib/gyp/generator/msvs.py
+++ b/pylib/gyp/generator/msvs.py
@@ -2624,6 +2624,10 @@ def _GetMSBuildGlobalProperties(spec, guid, gyp_file_name):
       ]
     ]
 
+  if os.environ.get('PROCESSOR_ARCHITECTURE') == 'AMD64' or \
+     os.environ.get('PROCESSOR_ARCHITEW6432') == 'AMD64':
+    properties[0].append(['PreferredToolArchitecture', 'x64'])
+
   if spec.get('msvs_enable_winrt'):
     properties[0].append(['DefaultLanguage', 'en-US'])
     properties[0].append(['AppContainerApplication', 'true'])