Add install target for 'extra-files'

So additional files like tests/calculateoverallcoverage.awk
and coding-style.clang-format are installed and can be used
by other projects, too.

CMakeLists.txt

@@ -94,7 +94,8 @@ set(CMAKE_TEMPLATE_FILES
     cmake/templates/global.h.in
     cmake/templates/template.pc.in
 )
-set(SCRIPT_FILES)
+set(SCRIPT_FILES
+)
 if(MINGW)
     list(APPEND CMAKE_TEMPLATE_FILES
         cmake/templates/windows.rc.in
@@ -109,6 +110,10 @@ set(DOC_FILES
     doc/buildvariables.md
     doc/testapplication.md
 )
+set(EXTRA_FILES
+    tests/calculateoverallcoverage.awk
+    coding-style.clang-format
+)
 
 # required to include CMake modules from own project directory
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules" "${CMAKE_MODULE_PATH}")

cmake/modules/BasicConfig.cmake

@@ -252,4 +252,19 @@ if(CLANG_SOURCE_BASED_COVERAGE_ENABLED)
     endif()
 endif()
 
+# add install target for extra files
+foreach(EXTRA_FILE ${EXTRA_FILES})
+    get_filename_component(EXTRA_DIR ${EXTRA_FILE} DIRECTORY)
+    install(
+        FILES ${EXTRA_FILE}
+        DESTINATION "share/${META_PROJECT_NAME}/${EXTRA_DIR}"
+        COMPONENT extra-files
+    )
+endforeach()
+if(NOT TARGET install-extra-files)
+    add_custom_target(install-extra-files
+        COMMAND "${CMAKE_COMMAND}" -DCMAKE_INSTALL_COMPONENT=extra-files -P "${CMAKE_BINARY_DIR}/cmake_install.cmake"
+    )
+endif()
+
 set(BASIC_PROJECT_CONFIG_DONE YES)