There's a builtin `toolpath` option we can use for that, so no need to hack
around a custom `scons_site` path.
The script requires SCons 3.1.1 or later, so we enable it conditionally.
Follow-up to #32848.
This tool is originally from mongodb.
- Updated CPPSUFFIXES to use scons suffixes
- objective-c files will also be loaded into the compilation database where the compiler / tooling is available to compile the files.
Known limitations:
- This will not work with msvc as your compiler.