Make all relevant targets available in the genex context.

The current node being evaluated transitively in the generator
expression must be available to resolve mapped configs.

Source/cmGeneratorExpression.cxx

@@ -53,7 +53,22 @@ cmGeneratorExpression::~cmGeneratorExpression()
 //----------------------------------------------------------------------------
 const char *cmCompiledGeneratorExpression::Evaluate(
   cmMakefile* mf, const char* config, bool quiet,
-  cmTarget *target,
+  cmTarget *headTarget,
+  cmGeneratorExpressionDAGChecker *dagChecker) const
+{
+  return this->Evaluate(mf,
+                        config,
+                        quiet,
+                        headTarget,
+                        headTarget,
+                        dagChecker);
+}
+
+//----------------------------------------------------------------------------
+const char *cmCompiledGeneratorExpression::Evaluate(
+  cmMakefile* mf, const char* config, bool quiet,
+  cmTarget *headTarget,
+  cmTarget *currentTarget,
   cmGeneratorExpressionDAGChecker *dagChecker) const
 {
   if (!this->NeedsParsing)
@@ -73,7 +88,8 @@ const char *cmCompiledGeneratorExpression::Evaluate(
   context.Config = config;
   context.Quiet = quiet;
   context.HadError = false;
-  context.Target = target;
+  context.HeadTarget = headTarget;
+  context.CurrentTarget = currentTarget ? currentTarget : headTarget;
   context.Backtrace = this->Backtrace;
 
   for ( ; it != end; ++it)

Source/cmGeneratorExpression.h

@@ -71,8 +71,13 @@ class cmCompiledGeneratorExpression
 public:
   const char* Evaluate(cmMakefile* mf, const char* config,
                        bool quiet = false,
-                       cmTarget *target = 0,
+                       cmTarget *headTarget = 0,
+                       cmTarget *currentTarget = 0,
                        cmGeneratorExpressionDAGChecker *dagChecker = 0) const;
+  const char* Evaluate(cmMakefile* mf, const char* config,
+                       bool quiet,
+                       cmTarget *headTarget,
+                       cmGeneratorExpressionDAGChecker *dagChecker) const;
 
   /** Get set of targets found during evaluations.  */
   std::set<cmTarget*> const& GetTargets() const

Source/cmGeneratorExpressionDAGChecker.cxx

@@ -57,7 +57,7 @@ void cmGeneratorExpressionDAGChecker::reportError(
     e << "Error evaluating generator expression:\n"
       << "  " << expr << "\n"
       << "Self reference on target \""
-      << context->Target->GetName() << "\".\n";
+      << context->HeadTarget->GetName() << "\".\n";
     context->Makefile->GetCMakeInstance()
       ->IssueMessage(cmake::FATAL_ERROR, e.str().c_str(),
                       parent->Backtrace);

Source/cmGeneratorExpressionEvaluator.cxx

@@ -297,7 +297,7 @@ static const struct TargetPropertyNode : public cmGeneratorExpressionNode
     cmsys::RegularExpression propertyNameValidator;
     propertyNameValidator.compile("^[A-Za-z0-9_]+$");
 
-    cmTarget* target = context->Target;
+    cmTarget* target = context->HeadTarget;
     std::string propertyName = *parameters.begin();
     if (parameters.size() == 2)
       {

Source/cmGeneratorExpressionEvaluator.h

@@ -26,7 +26,9 @@ struct cmGeneratorExpressionContext
   std::set<cmTarget*> Targets;
   cmMakefile *Makefile;
   const char *Config;
-  cmTarget *Target;
+  cmTarget *HeadTarget; // The target whose property is being evaluated.
+  cmTarget *CurrentTarget; // The dependent of HeadTarget which appears
+                           // directly or indirectly in the property.
   bool Quiet;
   bool HadError;
 };