fix installation

alpaka should not be installed if it is used as CMake subdirectory.
The reason is that alpaka is header only and the headers will not be
used after the master project used alpaka for compilation.

Author: psychocoderHPC

CMakeLists.txt

@@ -141,38 +141,42 @@ endif()
 
 ################################################################################
 # Installation.
-include(CMakePackageConfigHelpers)
-include(GNUInstallDirs)
-
-set(_ALPAKA_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/alpaka")
-
-install(TARGETS alpaka
-        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
-        
-write_basic_package_version_file(
-    "alpakaConfigVersion.cmake"
-    VERSION ${PROJECT_VERSION}
-    COMPATIBILITY SameMajorVersion)
-
-configure_package_config_file(
-    "${_ALPAKA_ROOT_DIR}/cmake/alpakaConfig.cmake.in"
-    "${PROJECT_BINARY_DIR}/alpakaConfig.cmake" 
-    INSTALL_DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
-
-install(FILES "${PROJECT_BINARY_DIR}/alpakaConfig.cmake"
-              "${PROJECT_BINARY_DIR}/alpakaConfigVersion.cmake"
-        DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
-
-install(DIRECTORY "${_ALPAKA_SUFFIXED_INCLUDE_DIR}"
-        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
-
-install(FILES "${_ALPAKA_ROOT_DIR}/cmake/addExecutable.cmake"
-              "${_ALPAKA_ROOT_DIR}/cmake/addLibrary.cmake"
-              "${_ALPAKA_ROOT_DIR}/cmake/alpakaCommon.cmake"
-              "${_ALPAKA_ROOT_DIR}/cmake/common.cmake"
-        DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
-
-install(DIRECTORY "${_ALPAKA_ROOT_DIR}/cmake/modules"
-        DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
+
+# Do not install if alpaka is used as a CMake subdirectory
+if(${CMAKE_PROJECT_NAME} STREQUAL ${PROJECT_NAME})
+    include(CMakePackageConfigHelpers)
+    include(GNUInstallDirs)
+
+    set(_ALPAKA_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/alpaka")
+
+    install(TARGETS alpaka
+            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+            RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
+    write_basic_package_version_file(
+        "alpakaConfigVersion.cmake"
+        VERSION ${PROJECT_VERSION}
+        COMPATIBILITY SameMajorVersion)
+
+    configure_package_config_file(
+        "${_ALPAKA_ROOT_DIR}/cmake/alpakaConfig.cmake.in"
+        "${PROJECT_BINARY_DIR}/alpakaConfig.cmake" 
+        INSTALL_DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
+
+    install(FILES "${PROJECT_BINARY_DIR}/alpakaConfig.cmake"
+                  "${PROJECT_BINARY_DIR}/alpakaConfigVersion.cmake"
+            DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
+
+    install(DIRECTORY "${_ALPAKA_SUFFIXED_INCLUDE_DIR}"
+            DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
+
+    install(FILES "${_ALPAKA_ROOT_DIR}/cmake/addExecutable.cmake"
+                  "${_ALPAKA_ROOT_DIR}/cmake/addLibrary.cmake"
+                  "${_ALPAKA_ROOT_DIR}/cmake/alpakaCommon.cmake"
+                  "${_ALPAKA_ROOT_DIR}/cmake/common.cmake"
+            DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
+
+    install(DIRECTORY "${_ALPAKA_ROOT_DIR}/cmake/modules"
+            DESTINATION "${_ALPAKA_INSTALL_CMAKEDIR}")
+endif()