message: Don't check soname on Windows
  This allow users to specify a certain CUDA version on Windows again.
  Without this, we get the following error:
  ```
  Cuda Configuration Error: None of the libraries match their SONAME: C:/Program Files/NVIDIA GPU Computing Toolkit/CUDA/v9.1/lib/x64/cudart.lib
  ```
diff: @@ -735,7 +735,7 @@ def find_lib(repository_ctx, paths, check_soname = True):
  for path in [repository_ctx.path(path) for path in paths]:
  if not path.exists:
  continue
  - if check_soname and objdump != None:
  + if check_soname and objdump != None and not _is_windows(repository_ctx):
  output = repository_ctx.execute([objdump, "-p", str(path)]).stdout
  output = [line for line in output.splitlines() if "SONAME" in line]
  sonames = [line.strip().split(" ")[-1] for line in output]
  