Replace occurrences of "Mac OS X" with "macOS" in comments

Apple's main Operating system changed their name from OS X to macOS:

    https://www.engadget.com/2016/06/13/os-x-is-now-macos/

Revise source comments accordingly.

Modules/FindBoost.cmake

@@ -493,11 +493,11 @@ function(_Boost_GUESS_COMPILER_PREFIX _ret)
           if(Boost_MINOR_VERSION)
             if(${Boost_MINOR_VERSION} GREATER 35)
               # In Boost 1.36.0 and newer, the mangled compiler name used
-              # on Mac OS X/Darwin is "xgcc".
+              # on macOS/Darwin is "xgcc".
               set(_boost_COMPILER "-xgcc${_boost_COMPILER_VERSION}")
             else()
               # In Boost <= 1.35.0, there is no mangled compiler name for
-              # the Mac OS X/Darwin version of GCC.
+              # the macOS/Darwin version of GCC.
               set(_boost_COMPILER "")
             endif()
           else()

Source/QtDialog/CMakeSetupDialog.cxx

@@ -108,7 +108,7 @@ CMakeSetupDialog::CMakeSetupDialog()
 
   QMenu* ToolsMenu = this->menuBar()->addMenu(tr("&Tools"));
   this->ConfigureAction = ToolsMenu->addAction(tr("&Configure"));
-  // prevent merging with Preferences menu item on Mac OS X
+  // prevent merging with Preferences menu item on macOS
   this->ConfigureAction->setMenuRole(QAction::NoRole);
   QObject::connect(this->ConfigureAction, SIGNAL(triggered(bool)), this,
                    SLOT(doConfigure()));

Source/QtDialog/QCMakeCacheView.cxx

@@ -614,7 +614,7 @@ bool QCMakeCacheModelDelegate::editorEvent(QEvent* e,
 // Can remove this function and FileDialogFlag when minimum Qt version is 4.5
 bool QCMakeCacheModelDelegate::eventFilter(QObject* object, QEvent* evt)
 {
-  // workaround for what looks like a bug in Qt on Mac OS X
+  // workaround for what looks like a bug in Qt on macOS
   // where it doesn't create a QWidget wrapper for the native file dialog
   // so the Qt library ends up assuming the focus was lost to something else
 

Source/cmComputeLinkInformation.cxx

@@ -30,7 +30,7 @@ Notes about linking on various platforms:
 
 ------------------------------------------------------------------------------
 
-Linux, FreeBSD, Mac OS X, IRIX, Sun, Windows:
+Linux, FreeBSD, macOS, IRIX, Sun, Windows:
 
 Linking to libraries using the full path works fine.
 

Source/cmLocalGenerator.cxx

@@ -1345,7 +1345,7 @@ void cmLocalGenerator::AddArchitectureFlags(std::string& flags,
                                             const std::string& lang,
                                             const std::string& config)
 {
-  // Only add Mac OS X specific flags on Darwin platforms (OSX and iphone):
+  // Only add macOS specific flags on Darwin platforms (macOS and iOS):
   if (this->Makefile->IsOn("APPLE") && this->EmitUniversalBinaryFlags) {
     std::vector<std::string> archs;
     target->GetAppleArchs(config, archs);

Source/cmLocalGenerator.h

@@ -300,14 +300,14 @@ public:
   std::string const& GetCurrentSourceDirectory() const;
 
   /**
-   * Generate a Mac OS X application bundle Info.plist file.
+   * Generate a macOS application bundle Info.plist file.
    */
   void GenerateAppleInfoPList(cmGeneratorTarget* target,
                               const std::string& targetName,
                               const char* fname);
 
   /**
-   * Generate a Mac OS X framework Info.plist file.
+   * Generate a macOS framework Info.plist file.
    */
   void GenerateFrameworkInfoPList(cmGeneratorTarget* target,
                                   const std::string& targetName,

Source/cmMakefileTargetGenerator.h

@@ -71,7 +71,7 @@ protected:
   // write the depend rules for this target
   void WriteTargetDependRules();
 
-  // write rules for Mac OS X Application Bundle content.
+  // write rules for macOS Application Bundle content.
   struct MacOSXContentGeneratorType
     : cmOSXBundleGenerator::MacOSXContentGeneratorType
   {
@@ -237,7 +237,7 @@ protected:
   std::string TargetNameImport;
   std::string TargetNamePDB;
 
-  // Mac OS X content info.
+  // macOS content info.
   std::set<std::string> MacContentFolders;
   cmOSXBundleGenerator* OSXBundleGenerator;
   MacOSXContentGeneratorType* MacOSXContentGenerator;

Source/cmNinjaTargetGenerator.h

@@ -135,7 +135,7 @@ protected:
   void EnsureDirectoryExists(const std::string& dir) const;
   void EnsureParentDirectoryExists(const std::string& path) const;
 
-  // write rules for Mac OS X Application Bundle content.
+  // write rules for macOS Application Bundle content.
   struct MacOSXContentGeneratorType
     : cmOSXBundleGenerator::MacOSXContentGeneratorType
   {