[clang] `intercept-build` can't find its Python modules on a `lib64` system

[mgorny]

$ intercept-build 
Traceback (most recent call last):
  File "/usr/lib/llvm/20/bin/intercept-build", line 13, in <module>
    from libscanbuild.intercept import intercept_build
ModuleNotFoundError: No module named 'libscanbuild'

As the OP pointed out, the code appends a hardcoded lib directory:

llvm-project/clang/tools/scan-build-py/bin/intercept-build

Lines 10 to 11 in c1248c9

	this_dir = os.path.dirname(os.path.realpath(__file__))
	sys.path.append(os.path.join(os.path.dirname(this_dir), 'lib'))

However, the files are installed in suffixed lib directory:

llvm-project/clang/tools/scan-build-py/CMakeLists.txt

Lines 90 to 92 in c1248c9

	install(FILES lib/libscanbuild/${lib}
	DESTINATION lib${CLANG_LIBDIR_SUFFIX}/libscanbuild
	COMPONENT scan-build-py)

I'm going to submit a pull request changing the install directory to lib to match. Since these are just Python modules, they don't need multilib.

Original bug report: https://bugs.gentoo.org/938665

[mgorny]

/cherry-pick 0c4cf79