[CMake] Store the custom compile_commands.json file in a sub-directory

https://bugs.webkit.org/show_bug.cgi?id=260769

Reviewed by Michael Catanzaro.

clangd and similar tools should be configured to look for the compile_commands.json file in the
DeveloperTools directory, so for GTK for instance, WebKitBuild/GTK/Release/DeveloperTools/.

* Source/cmake/WebKitCommon.cmake:
* Tools/Scripts/rewrite-compile-commands:

Canonical link: https://commits.webkit.org/267324@main

Source/cmake/WebKitCommon.cmake

@@ -240,12 +240,12 @@ if (NOT HAS_RUN_WEBKIT_COMMON)
     if (CMAKE_EXPORT_COMPILE_COMMANDS AND ENABLE_UNIFIED_BUILDS)
         add_custom_target(RewriteCompileCommands
             ALL
-            BYPRODUCTS webkit_compile_commands.json
+            BYPRODUCTS DeveloperTools/compile_commands.json
             DEPENDS "${CMAKE_BINARY_DIR}/compile_commands.json"
             COMMAND "${PYTHON_EXECUTABLE}"
                     "${CMAKE_SOURCE_DIR}/Tools/Scripts/rewrite-compile-commands"
                     "${CMAKE_BINARY_DIR}/compile_commands.json"
-                    "${CMAKE_BINARY_DIR}/webkit_compile_commands.json"
+                    "${CMAKE_BINARY_DIR}/DeveloperTools/compile_commands.json"
                     "${CMAKE_SOURCE_DIR}"
                     "${CMAKE_BINARY_DIR}"
         )

Tools/Scripts/rewrite-compile-commands

@@ -88,5 +88,9 @@ for entry in compile_commands:
             else:
                 print('Failed to find', include_path)
 
+output_directory = os.path.dirname(args.output_file)
+if not os.path.isdir(output_directory):
+    os.makedirs(output_directory)
+
 with open(args.output_file, 'w') as f:
     json.dump(generated_compile_commands, f, indent=2)