build: cmake: put generated sources into ${scylla_gen_build_dir}

to be aligned with the convention of configure.py

Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>

idl/CMakeLists.txt

@@ -2,15 +2,15 @@ find_package(Python3 COMPONENTS QUIET REQUIRED Interpreter)
 
 # Create C++ bindings for IDL serializers
 function(compile_idl input)
-  cmake_parse_arguments(parsed_args "" "SOURCES" "" ${ARGN})
+  cmake_parse_arguments(parsed_args "" "SOURCES;OUT_DIR" "" ${ARGN})
   get_filename_component(basename ${input} NAME_WE)
   get_filename_component(directory ${input} DIRECTORY)
   set(input "${CMAKE_CURRENT_SOURCE_DIR}/${input}")
   if(directory)
-    set(directory "${CMAKE_CURRENT_BINARY_DIR}/${directory}")
+    set(directory "${parsed_args_OUT_DIR}/${directory}")
     file(MAKE_DIRECTORY "${directory}")
   else()
-    set(directory "${CMAKE_CURRENT_BINARY_DIR}")
+    set(directory "${parsed_args_OUT_DIR}")
   endif()
   set(idl_compiler "${CMAKE_SOURCE_DIR}/idl-compiler.py")
   set(output "${directory}/${basename}.dist.hh")

rust/CMakeLists.txt

@@ -57,7 +57,7 @@ add_custom_command(
 generate_cxxbridge(wasmtime_bindings
   INPUT wasmtime_bindings/src/lib.rs
   INCLUDE ${cxx_header}
-  OUTPUT_DIR "${CMAKE_CURRENT_BINARY_DIR}"
+  OUTPUT_DIR "${scylla_gen_build_dir}"
   SOURCES wasmtime_bindings_sources)
 
 set_target_properties(Rust::rust_combined PROPERTIES