GENERATED prop: Add implementation for policy CMP0118 being set to NEW

* Adding implementation for policy CMP0118 being set to `NEW`.
* Adding new tests for policy CMP0118 being set to `NEW`.
* Checking the `GENERATED` property with `get_source_file_property` or
  `get_property` now always returns exactly `1` or `0`. No other values
  will be returned. Note, that this is a backwards-incompatible change,
  even when policy CMP0118 is unset or set to `OLD`.
* Additionally, as `get_source_file_property` and `get_property` now
  always check if a source-file was marked globally visible, even when
  CMP0118 is unset or set to `OLD`, they possibly return `1` where they
  might have returned `0` before the changes introduced by this commit.
  Note, that this is a backwards-incompatible change, even when policy
  CMP0118 is unset or set to `OLD`.
* As a consequence, the tests for policy CMP0118 being unset or set to
  `OLD` got slightly adjusted, too, to reflect these changes in
  behavior.

1 files changed, 8 insertions, 0 deletions

diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index afafba9..e933589 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -11,6 +11,7 @@
 #include <set>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -290,6 +291,11 @@ public:
 
   void AddInstallComponent(const std::string& component);
 
+  /** Mark the (absolute path to a) file as generated.  */
+  void MarkAsGeneratedFile(const std::string& filepath);
+  /** Determine if the absolute filepath belongs to a generated file.  */
+  bool IsGeneratedFile(const std::string& filepath);
+
   const std::set<std::string>* GetInstallComponents() const
   {
     return &this->InstallComponents;
@@ -722,6 +728,8 @@ private:
 
   std::map<std::string, std::string> RealPaths;
 
+  std::unordered_set<std::string> GeneratedFiles;
+
 #if !defined(CMAKE_BOOTSTRAP)
   // Pool of file locks
   cmFileLockPool FileLockPool;