GenEx: Report actual target name not found, not "0" each time.

Source/cmGeneratorExpressionEvaluator.cxx

@@ -278,14 +278,15 @@ static const struct TargetPropertyNode : public cmGeneratorExpressionNode
     std::string propertyName = *parameters.begin();
     if (parameters.size() == 2)
       {
+      std::string targetName = parameters.front();
       target = context->Makefile->FindGeneratorTargetToUse(
-                                                parameters.begin()->c_str());
+                                                targetName.c_str());
 
       if (!target)
         {
         cmOStringStream e;
         e << "Target \""
-          << target
+          << targetName
           << "\" not found.";
         reportError(context, content->GetOriginalExpression(), e.str());
         return std::string();

Tests/RunCMake/TargetPropertyGeneratorExpressions/BadNonTarget-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/TargetPropertyGeneratorExpressions/BadNonTarget-stderr.txt

@@ -0,0 +1,6 @@
+CMake Error:
+  Error evaluating generator expression:
+
+    \$<TARGET_PROPERTY:NonExistant,INCLUDE_DIRECTORIES>
+
+  Target "NonExistant" not found.$

Tests/RunCMake/TargetPropertyGeneratorExpressions/BadNonTarget.cmake

@@ -0,0 +1,7 @@
+
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/main.cpp"
+           "int main(int, char **) { return 0; }\n")
+
+add_executable(TargetPropertyGeneratorExpressions
+           "${CMAKE_CURRENT_BINARY_DIR}/main.cpp")
+include_directories("$<TARGET_PROPERTY:NonExistant,INCLUDE_DIRECTORIES>")

Tests/RunCMake/TargetPropertyGeneratorExpressions/RunCMakeTest.cmake

@@ -6,3 +6,4 @@ run_cmake(BadSelfReference3)
 run_cmake(BadSelfReference4)
 run_cmake(BadSelfReference5)
 run_cmake(BadSelfReference6)
+run_cmake(BadNonTarget)