libpi_cuda requires threads but Threads is not included via cmake

[Natrocx]

The error looks like this:

FAILED: lib/libpi_cuda.so
: && /usr/bin/g++-8 -fPIC -O3 -pipe -fexceptions -march=native -fasynchronous-unwind-tables -fPIC -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -fdiagnostics-color -ffunction-sections -fdata-sections -Wall -Wextra -Wno-deprecated-declarations -O3 -DNDEBUG  -Wl,-z,defs -Wl,-z,nodelete -Wl,--color-diagnostics -shared -Wl,-soname,libpi_cuda.so -o lib/libpi_cuda.so tools/sycl/plugins/cuda/CMakeFiles/pi_cuda.dir/pi_cuda.cpp.o  -Wl,-rpath,/opt/cuda/lib64:  /opt/cuda/lib64/libcuda.so  -lgcc_s  -lgcc && :
ld: error: undefined symbol: pthread_once
>>> referenced by pi_cuda.cpp
>>>               tools/sycl/plugins/cuda/CMakeFiles/pi_cuda.dir/pi_cuda.cpp.o:(cuda_piPlatformsGet)

This should easily be solved by adding find_package(Threads) and adding that to the target in the appropriate cmake file

[vladimirlaz]

@Natrocx, could you please share your cmake configuration and build command lines? Are you using top of the sycl branch? I do not see the problem in CI runs.

[Natrocx]

Hello,

this seems to have been fixed in a recent commit, I cannot replicate it after pulling.

Thank you for your time.