Modernize: Use #pragma once in all header files

#pragma once is a widely supported compiler pragma, even though it is
not part of the C++ standard. Many of the issues keeping #pragma once
from being standardized (distributed filesystems, build farms, hard
links, etc.) do not apply to CMake - it is easy to build CMake on a
single machine. CMake also does not install any header files which can
be consumed by other projects (though cmCPluginAPI.h has been
deliberately omitted from this conversion in case anyone is still using
it.) Finally, #pragma once has been required to build CMake since at
least August 2017 (7f29bbe6 enabled server mode unconditionally, which
had been using #pragma once since September 2016 (b13d3e0d)). The fact
that we now require C++11 filters out old compilers, and it is unlikely
that there is a compiler which supports C++11 but does not support
#pragma once.

Source/CursesDialog/cmCursesBoolWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesBoolWidget_h
-#define cmCursesBoolWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -29,5 +28,3 @@ public:
   void SetValueAsBool(bool value);
   bool GetValueAsBool();
 };
-
-#endif // cmCursesBoolWidget_h

Source/CursesDialog/cmCursesCacheEntryComposite.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesCacheEntryComposite_h
-#define cmCursesCacheEntryComposite_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -41,5 +40,3 @@ protected:
   int LabelWidth;
   int EntryWidth;
 };
-
-#endif // cmCursesCacheEntryComposite_h

Source/CursesDialog/cmCursesColor.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesColor_h
-#define cmCursesColor_h
+#pragma once
 
 class cmCursesColor
 {
@@ -23,5 +22,3 @@ public:
 protected:
   static short GetColor(char id, short fallback);
 };
-
-#endif // cmCursesColor_h

Source/CursesDialog/cmCursesDummyWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesDummyWidget_h
-#define cmCursesDummyWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -24,5 +23,3 @@ public:
   // handled.
   bool HandleInput(int& key, cmCursesMainForm* fm, WINDOW* w) override;
 };
-
-#endif // cmCursesDummyWidget_h

Source/CursesDialog/cmCursesFilePathWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesFilePathWidget_h
-#define cmCursesFilePathWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -15,5 +14,3 @@ public:
   cmCursesFilePathWidget(cmCursesFilePathWidget const&) = delete;
   cmCursesFilePathWidget& operator=(cmCursesFilePathWidget const&) = delete;
 };
-
-#endif // cmCursesFilePathWidget_h

Source/CursesDialog/cmCursesForm.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesForm_h
-#define cmCursesForm_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -62,5 +61,3 @@ protected:
 
   FORM* Form;
 };
-
-#endif // cmCursesForm_h

Source/CursesDialog/cmCursesLabelWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesLabelWidget_h
-#define cmCursesLabelWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -28,5 +27,3 @@ public:
   // handled
   bool HandleInput(int& key, cmCursesMainForm* fm, WINDOW* w) override;
 };
-
-#endif // cmCursesLabelWidget_h

Source/CursesDialog/cmCursesLongMessageForm.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesLongMessageForm_h
-#define cmCursesLongMessageForm_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -59,5 +58,3 @@ protected:
 
   FIELD* Fields[2];
 };
-
-#endif // cmCursesLongMessageForm_h

Source/CursesDialog/cmCursesMainForm.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesMainForm_h
-#define cmCursesMainForm_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -170,5 +169,3 @@ protected:
   std::string OldSearchString;
   bool SearchMode;
 };
-
-#endif // cmCursesMainForm_h

Source/CursesDialog/cmCursesOptionsWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesOptionsWidget_h
-#define cmCursesOptionsWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -35,5 +34,3 @@ protected:
   std::vector<std::string> Options;
   std::vector<std::string>::size_type CurrentOption;
 };
-
-#endif // cmCursesOptionsWidget_h

Source/CursesDialog/cmCursesPathWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesPathWidget_h
-#define cmCursesPathWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -34,5 +33,3 @@ protected:
   bool Cycle;
   std::string::size_type CurrentIndex;
 };
-
-#endif // cmCursesPathWidget_h

Source/CursesDialog/cmCursesStandardIncludes.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesStandardIncludes_h
-#define cmCursesStandardIncludes_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -41,5 +40,3 @@ inline void curses_clear()
 #  undef __attribute__
 #endif
 #undef cm_no__attribute__
-
-#endif // cmCursesStandardIncludes_h

Source/CursesDialog/cmCursesStringWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesStringWidget_h
-#define cmCursesStringWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -65,5 +64,3 @@ protected:
   std::string OriginalString;
   bool Done;
 };
-
-#endif // cmCursesStringWidget_h

Source/CursesDialog/cmCursesWidget.h

@@ -1,7 +1,6 @@
 /* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
    file Copyright.txt or https://cmake.org/licensing for details.  */
-#ifndef cmCursesWidget_h
-#define cmCursesWidget_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -68,5 +67,3 @@ protected:
   // The page in the main form this widget is in
   int Page;
 };
-
-#endif // cmCursesWidget_h