cmake: always generate compile commands

Generating compilation commands consumes negligible time on our scale of
build. DuckDB enables the generation by [default][1]. Also, this automatic
generation eases integrations with editors and tools like clang-tidy.

  [1]: https://github.com/duckdb/duckdb/blob/173a690d18058ca1021b3241653eec27d07eb2df/CMakeLists.txt#L23

CMakeLists.txt

@@ -8,6 +8,7 @@ set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
 set(CMAKE_CXX_VISIBILITY_PRESET hidden)
 set(CMAKE_C_VISIBILITY_PRESET hidden)
+set(CMAKE_EXPORT_COMPILE_COMMANDS TRUE)
 set(CMAKE_FIND_PACKAGE_RESOLVE_SYMLINKS TRUE)
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 set(CMAKE_VISIBILITY_INLINES_HIDDEN ON)

Makefile

@@ -157,17 +157,15 @@ shell:
 
 
 # Clang-related tools and checks
-clangd:
-	$(call config-cmake-release, -DCMAKE_EXPORT_COMPILE_COMMANDS=1)
 
 # Must build the java native header to avoid missing includes. Pipe character
 # `|` ensures these targets build in this order, even in the presence of
 # parallelism.
-tidy: | allconfig clangd java_native_header
+tidy: | allconfig java_native_header
 	run-clang-tidy -p build/release -quiet -j $(NUM_THREADS) \
 		"^$(realpath src)|$(realpath tools)/(?!shell/linenoise.cpp)|$(realpath examples)"
 
-clangd-diagnostics: | allconfig clangd java_native_header
+clangd-diagnostics: | allconfig java_native_header
 	find src -name *.h -or -name *.cpp | xargs \
 		./scripts/get-clangd-diagnostics.py --compile-commands-dir build/release \
 		-j $(NUM_THREADS) --instances $(CLANGD_DIAGNOSTIC_INSTANCES)