[FRONTEND] Update path for headers to support Python 3.10 (#1123)

Python 3.10 changes where packages are installed by default, causing
problems with Ubuntu into `/local`. See
[this](https://lists.debian.org/debian-python/2022/03/msg00039.html) and
[this](https://bugs.launchpad.net/ubuntu/+source/python3.10/+bug/1967920).
Triton seems to break when using 3.10 as it looks for the headers, but
the headers are not in `/local`, e.g. they are at
`/usr/include/python3.X` and not `/usr/local/include/python3.X`


Not 100% sure what's going on here since it's deep in python / pip, but
I think this should fix it. Otherwise, you have to hack around it in
dockerfiles, e.g. `ENV DEB_PYTHON_INSTALL_LAYOUT=deb`, which breaks
things with the release of pip that went.

---------

Co-authored-by: Keren Zhou <kerenzhou@openai.com>

python/triton/compiler.py

@@ -16,7 +16,6 @@ import tempfile
 import warnings
 from collections import namedtuple
 from pathlib import Path
-from sysconfig import get_paths
 from typing import Any, Callable, Dict, Tuple, Union
 
 import setuptools
@@ -1393,7 +1392,16 @@ def _build(name, src, srcdir):
         cc = gcc if gcc is not None else clang
         if cc is None:
             raise RuntimeError("Failed to find C compiler. Please specify via CC environment variable.")
-    py_include_dir = get_paths()["include"]
+    # This function was renamed and made public in Python 3.10
+    if hasattr(sysconfig, 'get_default_scheme'):
+        scheme = sysconfig.get_default_scheme()
+    else:
+        scheme = sysconfig._get_default_scheme()
+    # 'posix_local' is a custom scheme on Debian. However, starting Python 3.10, the default install
+    # path changes to include 'local'. This change is required to use triton with system-wide python.
+    if scheme == 'posix_local':
+        scheme = 'posix_prefix'
+    py_include_dir = sysconfig.get_paths(scheme=scheme)["include"]
 
     cc_cmd = [cc, src, "-O3", f"-I{cu_include_dir}", f"-I{py_include_dir}", f"-I{srcdir}", "-shared", "-fPIC", "-lcuda", "-o", so]
     cc_cmd += [f"-L{dir}" for dir in cuda_lib_dirs]