Fix CUDA 8 build on Windows (pytorch#11729)

Summary:
Tested via pytorch#11374.
Upstream PR: https://gitlab.kitware.com/cmake/cmake/merge_requests/2391
Pull Request resolved: pytorch#11729

Differential Revision: D9847807

Pulled By: orionr

fbshipit-source-id: 69af3e6c5bba0abcbc8830495e867a0b1b399c22

README.md

@@ -201,9 +201,8 @@ set DISTUTILS_USE_SDK=1
 REM The following two lines are needed for Python 2.7, but the support for it is very experimental.
 set MSSdk=1
 set FORCE_PY27_BUILD=1
-REM As for CUDA 8, VS2015 Update 3 is also required to build PyTorch. Use the following two lines.
-set "PREBUILD_COMMAND=%VS140COMNTOOLS%\..\..\VC\vcvarsall.bat"
-set PREBUILD_COMMAND_ARGS=x64
+REM As for CUDA 8, VS2015 Update 3 is also required to build PyTorch. Use the following line.
+set "CUDA_HOST_COMPILER=%VS140COMNTOOLS%\..\..\VC\bin\amd64\cl.exe"
 
 call "%VS150COMNTOOLS%\vcvarsall.bat" x64 -vcvars_ver=14.11
 python setup.py install

cmake/Modules_CUDA_fix/upstream/FindCUDA.cmake

@@ -531,7 +531,9 @@ option(CUDA_HOST_COMPILATION_CPP "Generated file extension" ON)
 # Extra user settable flags
 cmake_initialize_per_config_variable(CUDA_NVCC_FLAGS "Semi-colon delimit multiple arguments.")
 
-if(CMAKE_GENERATOR MATCHES "Visual Studio")
+if(DEFINED ENV{CUDA_HOST_COMPILER})
+  set(CUDA_HOST_COMPILER "$ENV{CUDA_HOST_COMPILER}" CACHE FILEPATH "Host side compiler used by NVCC")
+elseif(CMAKE_GENERATOR MATCHES "Visual Studio")
   set(_CUDA_MSVC_HOST_COMPILER "$(VCInstallDir)Tools/MSVC/$(VCToolsVersion)/bin/Host$(Platform)/$(PlatformTarget)")
   if(MSVC_VERSION LESS 1910)
    set(_CUDA_MSVC_HOST_COMPILER "$(VCInstallDir)bin")