Don't abort if clang-format cannot be found

cmake/ClangFormat.cmake

@@ -14,7 +14,12 @@ function(prefix_clangformat_setup prefix)
       set(CLANGFORMAT_EXECUTABLE ${clangformat_executable_tmp})
       unset(clangformat_executable_tmp)
     else()
-      message(FATAL_ERROR "ClangFormat: ${CLANGFORMAT_EXECUTABLE} not found! Aborting")
+      if (CLANGFORMAT_FORCED)
+        message(FATAL_ERROR "ClangFormat: ${CLANGFORMAT_EXECUTABLE} not found! Aborted.")
+      else()
+        message(STATUS "ClangFormat: ${CLANGFORMAT_EXECUTABLE} not found! clangformat target will not be available.")
+        return()
+      endif()
     endif()
   endif()
 

example/CMakeLists.txt

@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.10)
+project(example-clang-format-cmake)
+
+include(../cmake/ClangFormat.cmake)
+
+add_Executable(${PROJECT_NAME} main.cpp)
+
+# Set the following to ON to abort CMake's configuration process if clang-format could not be found.
+# On default, it will just emit a status message and continue without creating the clangformat target.
+set(CLANGFORMAT_FORCED OFF)
+target_clangformat_setup(${PROJECT_NAME})
+

example/main.cpp

@@ -0,0 +1,6 @@
+#include <iostream>
+
+int main() {
+  std::cout << "Hello World" << std::endl;
+  return 0;
+}