Fix make and ninja backends to sensibly handle duplicate target names in different directories

pylib/gyp/generator/make.py

Index: pylib/gyp/generator/make.py
diff --git a/pylib/gyp/generator/make.py b/pylib/gyp/generator/make.py
index 8fde23cfbb9868c6517702141074fe625f59dc0d..4f56aa048355e33bb9b52e73e921c3f0ace4828b 100644
--- a/pylib/gyp/generator/make.py
+++ b/pylib/gyp/generator/make.py
@@ -598,8 +598,7 @@ def QuoteIfNecessary(string):
 
 def StringToMakefileVariable(string):
   """Convert a string to a value that is acceptable as a make variable name."""
-  # TODO: replace other metacharacters that we encounter.
-  return re.sub('[ {}$]', '_', string)
+  return re.sub('[^a-zA-Z0-9_]', '_', string)
 
 
 srcdir_prefix = ''
@@ -691,6 +690,7 @@ $(obj).$(TOOLSET)/$(TARGET)/%%.o: $(obj)/%%%s FORCE_DO_CMD
 
     self.fp.write(header)
 
+    self.qualified_target = qualified_target
     self.path = base_path
     self.target = spec['target_name']
     self.type = spec['type']
@@ -837,7 +837,8 @@ $(obj).$(TOOLSET)/$(TARGET)/%%.o: $(obj)/%%%s FORCE_DO_CMD
     part_of_all: flag indicating this target is part of 'all'
     """
     for action in actions:
-      name = self.target + '_' + StringToMakefileVariable(action['action_name'])
+      name = StringToMakefileVariable('%s_%s' % (self.qualified_target,
+                                                 action['action_name']))
       self.WriteLn('### Rules for action "%s":' % action['action_name'])
       inputs = action['inputs']
       outputs = action['outputs']
@@ -931,7 +932,8 @@ $(obj).$(TOOLSET)/$(TARGET)/%%.o: $(obj)/%%%s FORCE_DO_CMD
     part_of_all: flag indicating this target is part of 'all'
     """
     for rule in rules:
-      name = self.target + '_' + StringToMakefileVariable(rule['rule_name'])
+      name = StringToMakefileVariable('%s_%s' % (self.qualified_target,
+                                                 rule['rule_name']))
       count = 0
       self.WriteLn('### Generated for rule %s:' % name)
 
@@ -1046,7 +1048,7 @@ $(obj).$(TOOLSET)/$(TARGET)/%%.o: $(obj)/%%%s FORCE_DO_CMD
     """
     self.WriteLn('### Generated for copy rule.')
 
-    variable = self.target + '_copies'
+    name = StringToMakefileVariable(self.qualified_target + '_copies')
     outputs = []
     for copy in copies:
       for path in copy['files']: