Fix Clang-tidy error due to declarations in Colvars headers for code …

…not used in GROMACS

Attempt at solving https://gitlab.com/gromacs/gromacs/-/merge_requests/3671#note_1637345339

This change extends the same treatment used in `admin/clang-tidy.sh` to the CMake recipe.

src/gromacs/CMakeLists.txt

@@ -452,8 +452,10 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
 endif()
 
 if (GMX_CLANG_TIDY)
+   # Temporarily exclude Colvars headers to silence warnings from code that is not built with GROMACS
+   # TODO: remove this when clang-tidy >= 14 is used
    set_target_properties(libgromacs PROPERTIES CXX_CLANG_TIDY
-       "${CLANG_TIDY_EXE};-warnings-as-errors=*")
+       "${CLANG_TIDY_EXE};-warnings-as-errors=*;-header-filter=^(?!.*src/external/colvars).*")
 endif()
 
 # TODO: Stop installing libgromacs. Possibly allow installation during deprecation period with GMX_INSTALL_LEGACY_API.

src/testutils/TestMacros.cmake

@@ -78,7 +78,7 @@ function (gmx_add_unit_test_library NAME)
         endif()
         if(GMX_CLANG_TIDY)
             set_target_properties(${NAME} PROPERTIES CXX_CLANG_TIDY
-                "${CLANG_TIDY_EXE};-warnings-as-errors=*;-header-filter=.*")
+                "${CLANG_TIDY_EXE};-warnings-as-errors=*;-header-filter=^(?!.*src/external/colvars).*")
         endif()
         gmx_warn_on_everything(${NAME})
         if (HAS_WARNING_EVERYTHING)
@@ -235,7 +235,7 @@ function (gmx_add_gtest_executable EXENAME)
 
         if(GMX_CLANG_TIDY)
             set_target_properties(${EXENAME} PROPERTIES CXX_CLANG_TIDY
-                "${CLANG_TIDY_EXE};-warnings-as-errors=*;-header-filter=.*")
+                "${CLANG_TIDY_EXE};-warnings-as-errors=*;-header-filter=^(?!.*src/external/colvars).*")
         endif()
         gmx_warn_on_everything(${EXENAME})
         if (HAS_WARNING_EVERYTHING)