Starting with CUDA 10.2 the nvcc compiler has gained support
to automatically forward unknown flags to the host compiler.
This behavior is highly desired as projcts that mix CUDA, C, C++
run into situation where flags such as `-pthread` which aren't
supported by nvcc, are being applied to all source files and
therefore break CUDA compilation.
Default to the same flag that is used for verbose link information, but
provide another internal platform information variable to use a
compilation-specific variant. Populate it for CUDA where we use a
different compiler for compilation and linking and therefore need
different flags.
Co-Author: Chuck Cranor <chuck@ece.cmu.edu>
Starting in CUDA 9 the default compilation mode is C++14, and you need
to explicitly enable C++98/03 mode.
While at it, document `14` among the values for `CUDA_STANDARD`. This
was accidentally left out of commit v3.9.0-rc1~118^2 (CUDA: Add support
for the C++14 standard flag, 2017-05-11).
Fix the default values of `CMAKE_CUDA_FLAGS[_<CONFIG>]` on Windows to
make the host compiler flags match those produced for C++ by the
`Platform/Windows-MSVC` module. This makes the flags consistent with
those used for C++.
Port Windows-specific compilation and linking rules over from the
`Platform/Windows-MSVC` module and adapt it for NVIDIA CUDA. On Windows
nvcc and its host compiler (MSVC) do not understand or use options like
`-fPIC` or `-std=`, so condition those out.
Since commit v3.7.0-rc1~392^2 (Honor CMAKE_<LANG>_FLAGS[_<CONFIG>]_INIT
set in toolchain files, 2016-07-05) our convention is to initialize
compiler flag variables via `string(APPEND)` rather than `set()`.
Fix the convention for `CMAKE_CUDA_FLAGS[_<CONFIG>]_INIT`.
