Makes analyzer strip off a leading path separator

pylib/gyp/generator/analyzer.py

Index: pylib/gyp/generator/analyzer.py
diff --git a/pylib/gyp/generator/analyzer.py b/pylib/gyp/generator/analyzer.py
index 007d17d17e183f470664b1d3f1fcf1fce13b9ced..77e46472a6bca3e45a5949ada4eb564a4faface0 100644
--- a/pylib/gyp/generator/analyzer.py
+++ b/pylib/gyp/generator/analyzer.py
@@ -40,6 +40,8 @@ def __MakeRelativeTargetName(path):
   prune_path = os.getcwd()
   if path.startswith(prune_path):
     path = path[len(prune_path):]
+    if len(path) and path.startswith(os.sep):
+      path = path[len(os.sep):]
   # Gyp paths are always posix style.
   path = path.replace('\\', '/')
   if path.endswith('#target'):
@@ -166,6 +168,15 @@ def CalculateVariables(default_variables, params):
     default_variables.setdefault('OS', 'mac')
   elif flavor == 'win':
     default_variables.setdefault('OS', 'win')
+    # Copy additional generator configuration data from VS, which is shared
+    # by the Windows Ninja generator.
+    import gyp.generator.msvs as msvs_generator
+    generator_additional_non_configuration_keys = getattr(msvs_generator,
+        'generator_additional_non_configuration_keys', [])
+    generator_additional_path_sections = getattr(msvs_generator,
+        'generator_additional_path_sections', [])
+
+    gyp.msvs_emulation.CalculateCommonVariables(default_variables, params)
   else:
     operating_system = flavor
     if flavor == 'android':