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.

5 files changed, 5 insertions, 20 deletions

diff --git a/Source/CPack/IFW/cmCPackIFWCommon.h b/Source/CPack/IFW/cmCPackIFWCommon.h
index 354d849..95ed213 100644
--- a/Source/CPack/IFW/cmCPackIFWCommon.h
+++ b/Source/CPack/IFW/cmCPackIFWCommon.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 cmCPackIFWCommon_h
-#define cmCPackIFWCommon_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -77,5 +76,3 @@ protected:
                              cmCPackLog_msg.str().c_str());                   \
     }                                                                         \
   } while (false)
-
-#endif // cmCPackIFWCommon_h
diff --git a/Source/CPack/IFW/cmCPackIFWGenerator.h b/Source/CPack/IFW/cmCPackIFWGenerator.h
index 86a73c8..024d25d 100644
--- a/Source/CPack/IFW/cmCPackIFWGenerator.h
+++ b/Source/CPack/IFW/cmCPackIFWGenerator.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 cmCPackIFWGenerator_h
-#define cmCPackIFWGenerator_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -152,5 +151,3 @@ private:
   std::vector<std::string> PkgsDirsVector;
   std::vector<std::string> RepoDirsVector;
 };
-
-#endif
diff --git a/Source/CPack/IFW/cmCPackIFWInstaller.h b/Source/CPack/IFW/cmCPackIFWInstaller.h
index 8b3f96a..6f398e3 100644
--- a/Source/CPack/IFW/cmCPackIFWInstaller.h
+++ b/Source/CPack/IFW/cmCPackIFWInstaller.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 cmCPackIFWInstaller_h
-#define cmCPackIFWInstaller_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -132,5 +131,3 @@ protected:
   void printSkippedOptionWarning(const std::string& optionName,
                                  const std::string& optionValue);
 };
-
-#endif // cmCPackIFWInstaller_h
diff --git a/Source/CPack/IFW/cmCPackIFWPackage.h b/Source/CPack/IFW/cmCPackIFWPackage.h
index 6a4a170..dbd5540 100644
--- a/Source/CPack/IFW/cmCPackIFWPackage.h
+++ b/Source/CPack/IFW/cmCPackIFWPackage.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 cmCPackIFWPackage_h
-#define cmCPackIFWPackage_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -149,5 +148,3 @@ public:
   // Patch to package directory
   std::string Directory;
 };
-
-#endif // cmCPackIFWPackage_h
diff --git a/Source/CPack/IFW/cmCPackIFWRepository.h b/Source/CPack/IFW/cmCPackIFWRepository.h
index c293981..21afd8b 100644
--- a/Source/CPack/IFW/cmCPackIFWRepository.h
+++ b/Source/CPack/IFW/cmCPackIFWRepository.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 cmCPackIFWRepository_h
-#define cmCPackIFWRepository_h
+#pragma once
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
@@ -84,5 +83,3 @@ public:
   RepositoriesVector RepositoryUpdate;
   std::string Directory;
 };
-
-#endif // cmCPackIFWRepository_h