[ML] Silence warnings stemming from PyTorch headers (#2152)

On Windows a number of deprecation warnings are seen emanating from
PyTorch header files (See #2120). An issue has been opened on the
PyTorch repo requesting that these deprecations be addressed
(pytorch/pytorch#69290). While the issue has
been triaged it is suspected that it will be some time before fixes are
forthcoming. These changes silence such deprecation warnings for
pytorch_inference only.

Author: edsavage

bin/pytorch_inference/Makefile

@@ -22,6 +22,13 @@ USE_NET=1
 USE_RAPIDJSON=1
 USE_TORCH=1
 
+# These lines can be removed once PyTorch code is updated to avoid using features
+# that are deprecated in C++17 (and will be removed in C++20).
+# See https://github.com/pytorch/pytorch/issues/69290
+ifeq ($(OS),Windows)
+    CPPFLAGS+=-D_HAS_FEATURES_REMOVED_IN_CXX20 -D_SILENCE_ALL_CXX17_DEPRECATION_WARNINGS
+endif
+
 LIBS=$(ML_LIBS)
 
 all: build