Merge topic 'apple-merge-same-sysroot'

3a7d1e9592 Apple: Merge per-arch sysroot parameters if all are the same

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !4647

Source/cmLocalGenerator.h

@@ -538,6 +538,8 @@ private:
                                    int targetType);
 
   void ComputeObjectMaxPath();
+  bool AllAppleArchSysrootsAreTheSame(const std::vector<std::string>& archs,
+                                      const char* sysroot);
 };
 
 #if !defined(CMAKE_BOOTSTRAP)