CMake: add option to disable pre-compiled headers

./tools/utils_maintenance/code_clean failed to operate on any sources
that used pre-compiled headers.

CMakeLists.txt

@@ -259,6 +259,28 @@ else()
   set(WITH_UNITY_BUILD OFF)
 endif()
 
+if(COMMAND target_precompile_headers)
+  # Disabling is needed for `./tools/utils_maintenance/code_clean.py` to function.
+  option(WITH_COMPILER_PRECOMPILED_HEADERS "\
+Use pre-compiled headers to speed up compilation."
+    ON
+  )
+  mark_as_advanced(WITH_COMPILER_PRECOMPILED_HEADERS)
+
+  if(WITH_CLANG_TIDY AND CMAKE_COMPILER_IS_GNUCC)
+    if(WITH_COMPILER_PRECOMPILED_HEADERS)
+      message(STATUS
+        "Clang-Tidy and GCC precompiled headers are incompatible, disabling precompiled headers"
+      )
+      set(WITH_COMPILER_PRECOMPILED_HEADERS OFF)
+    endif()
+  endif()
+
+  if(NOT WITH_COMPILER_PRECOMPILED_HEADERS)
+    set(CMAKE_DISABLE_PRECOMPILE_HEADERS ON)
+  endif()
+endif()
+
 option(WITH_IK_ITASC "\
 Enable ITASC IK solver (only disable for development & for incompatible C++ compilers)"
   ON

source/CMakeLists.txt

@@ -7,14 +7,6 @@ if(WITH_LEGACY_OPENGL)
 endif()
 
 if(WITH_CLANG_TIDY AND NOT MSVC)
-  if(NOT CMAKE_C_COMPILER_ID MATCHES "Clang")
-    message(WARNING "Currently Clang-Tidy might fail with GCC toolchain, switch to Clang toolchain if that happens")
-    if(COMMAND target_precompile_headers)
-      message(STATUS "Clang-Tidy and GCC precompiled headers are incompatible, disabling precompiled headers")
-      set(CMAKE_DISABLE_PRECOMPILE_HEADERS ON)
-    endif()
-  endif()
-
   find_package(ClangTidy REQUIRED)
   set(CMAKE_C_CLANG_TIDY
     ${CLANG_TIDY_EXECUTABLE};--extra-arg=-Wno-error=unknown-warning-option)

tools/utils_maintenance/code_clean.py

@@ -327,7 +327,7 @@ def process_commands(cmake_dir: str, data: Sequence[str]) -> Optional[ProcessedC
         return None
 
     # Check for unsupported configurations.
-    for arg in ("WITH_UNITY_BUILD", "WITH_COMPILER_CCACHE"):
+    for arg in ("WITH_UNITY_BUILD", "WITH_COMPILER_CCACHE", "WITH_COMPILER_PRECOMPILED_HEADERS"):
         if cmake_cache_var_is_true(cmake_cache_var(cmake_dir, arg)):
             sys.stderr.write("The option '%s' must be disabled for proper functionality\n" % arg)
             return None