Changes according to review

We need first clang-tidy for all

If found, we should find run-clang-tidy.py for the check taget
Then we need a compile_commands.json created by cmake or mesonbuild.

And this has to be linkd to the source tree, if the binary tree is
outsite the source tree.

That must be true for ninja generator to generate absolute pathes at
compile_commands.json!

cmake/clang-tidy.cmake

@@ -1,15 +1,18 @@
-option(ENABLE_CLANG_TIDY "Add run-clang-tidy automatically to builds" OFF)
+option(SPDLOG_ENABLE_TIDY "Add clang-tidy automatically as prebuild step" OFF)
+
 find_program(CLANG_TIDY_EXE
-        NAMES run-clang-tidy.py run-clang-tidy run-clang-tidy-7
+        NAMES clang-tidy clang-tidy-7
-        HINTS ${CMAKE_CURRENT_SOURCE_DIR}/scripts
         DOC "Path to clang-tidy executable")
+find_program(CLANG_TIDY_RUNNER
+        NAMES run-clang-tidy run-clang-tidy-7 run-clang-tidy.py
+        HINTS ${CMAKE_CURRENT_SOURCE_DIR}/scripts)
 if(CLANG_TIDY_EXE)
     message(STATUS "clang-tidy found: ${CLANG_TIDY_EXE}")
     set(DCMAKE_EXPORT_COMPILE_COMMANDS ON)
     set(CLANG_TIDY_CMD ${CLANG_TIDY_EXE})
     message(STATUS "cmake source dir: ${CMAKE_CURRENT_SOURCE_DIR}")
 
-    if(ENABLE_CLANG_TIDY)
+    if(SPDLOG_ENABLE_TIDY)
         # NOTE: the project config file .clang-tidy is not found if the
         # binary tree is not part of the source tree! CK
         set(CMAKE_CXX_CLANG_TIDY ${CLANG_TIDY_CMD} CACHE STRING "" FORCE)
@@ -17,6 +20,7 @@ if(CLANG_TIDY_EXE)
         set(CMAKE_CXX_CLANG_TIDY "" CACHE STRING "" FORCE) # delete it
     endif()
 
+    if(CLANG_TIDY_RUNNER)
         if(NOT TARGET check)
             add_custom_target(check)
             message(STATUS "check target added")
@@ -26,11 +30,12 @@ if(CLANG_TIDY_EXE)
         add_custom_command(TARGET check PRE_BUILD
             # -p BUILD_PATH Path used to read a compile command database (compile_commands.json).
             # NOTE: we use defaults checks from .clang-tidy and examples only!
-        COMMAND ${CLANG_TIDY_EXE} -p ${CMAKE_CURRENT_BINARY_DIR} ### ${CMAKE_CURRENT_SOURCE_DIR}/example
+            COMMAND ${CLANG_TIDY_RUNNER} -p ${CMAKE_CURRENT_BINARY_DIR} ### ${CMAKE_CURRENT_SOURCE_DIR}/example
             WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"   # location of compile_commands.json
             COMMENT "Running check on targets at ${CMAKE_CURRENT_SOURCE_DIR} ..."
             VERBATIM
         )
+    endif()
 else()
-    message(AUTHOR_WARNING "run-clang-tidy not found!")
+    message(AUTHOR_WARNING "clang-tidy not found!")
 endif()