Build RMM's Python bindings with PTDS

Defines `CUDA_API_PER_THREAD_DEFAULT_STREAM` for Setuptools `Extensions`
built by `setup.py`. This should make sure the per-thread default stream
is used by these Python extensions.

https://docs.nvidia.com/cuda/cuda-runtime-api/stream-sync-behavior.html

CHANGELOG.md

@@ -5,6 +5,7 @@
 ## Improvements
 
 - PR #477 Just use `None` for `strides` in `DeviceBuffer`
+- PR #480 Build RMM's Python bindings with PTDS
 
 ## Bug Fixes
 

python/setup.py

@@ -77,6 +77,10 @@ def get_cuda_version_from_header(cuda_include_dir):
 except Exception:
     nthreads = 0
 
+define_macros = [
+    ("CUDA_API_PER_THREAD_DEFAULT_STREAM", None),
+]
+
 include_dirs = [
     "../include/rmm",
     "../include",
@@ -125,6 +129,7 @@ def get_cuda_version_from_header(cuda_include_dir):
             ],
             libraries=["cuda", "rmm"],
             language="c++",
+            define_macros=define_macros,
             extra_compile_args=["-std=c++14"],
         )
     ],
@@ -148,6 +153,7 @@ def get_cuda_version_from_header(cuda_include_dir):
             ],
             libraries=["cuda", "rmm"],
             language="c++",
+            define_macros=define_macros,
             extra_compile_args=["-std=c++14"],
         )
     ],