Fix the tests for evaluating includes and defines.

We should also check whether the INTERFACE_ variant of a property
is being read, and in the case of the compile definitions, we should
test the _<CONFIG> suffixed variants. That is already available
through the use of the methods.

This way, we use the ALREADY_SEEN optimization when evaluating
the includes of a target in 'external' generator expressions, ie, those
used in a add_custom_command invokation, as opposed to evaluating the
INCLUDE_DIRECTORIES of a target itself via GetIncludeDirectories.

Source/cmGeneratorExpressionDAGChecker.cxx

@@ -33,8 +33,8 @@ cmGeneratorExpressionDAGChecker::cmGeneratorExpressionDAGChecker(
     }
   this->CheckResult = this->checkGraph();
 
-  if (CheckResult == DAG && (top->Property == "INCLUDE_DIRECTORIES"
-      || top->Property == "COMPILE_DEFINITIONS") )
+  if (CheckResult == DAG && (top->EvaluatingIncludeDirectories()
+      || top->EvaluatingCompileDefinitions()))
     {
     std::map<cmStdString, std::set<cmStdString> >::const_iterator it
                                                     = top->Seen.find(target);

Tests/GeneratorExpression/check-part2.cmake

@@ -26,11 +26,11 @@ check(test_build_interface "build")
 check(test_install_interface "")
 check(test_target_name_1 "tgt,ok")
 check(test_target_name_2 "tgt:ok")
-check(test_target_includes1 "/empty1/public;/empty2/public;/empty3/public;/empty4/public;/empty4/public")
-check(test_target_includes2 "/empty2/public;/empty3/public;/empty4/public;/empty4/public")
-check(test_target_includes3 "/empty3/public;/empty2/public;/empty4/public;/empty4/public")
+check(test_target_includes1 "/empty1/public;/empty2/public;/empty3/public;/empty4/public")
+check(test_target_includes2 "/empty2/public;/empty3/public;/empty4/public")
+check(test_target_includes3 "/empty3/public;/empty2/public;/empty4/public")
 check(test_target_includes4 "/empty1/public;/empty1/private;/empty2/public;/empty3/public;/empty4/public")
 check(test_target_includes5 "/empty2/public;/empty3/public;/empty2/public;/empty4/public")
 check(test_target_includes6 "/empty3/public;/empty3/private;/empty2/public;/empty3/public;/empty4/public")
-check(test_target_includes7 "/empty1/public;/empty2/public;/empty3/public;/empty4/public;/empty4/public")
+check(test_target_includes7 "/empty1/public;/empty2/public;/empty3/public;/empty4/public")
 check(test_target_includes8 "/empty5/private1;/empty5/private2")