Fix cmake scripts so projects using CUDA .cu files build correctly. (#1441)

tools/pybind11Tools.cmake

@@ -156,6 +156,7 @@ function(pybind11_add_module target_name)
   # namespace; also turning it on for a pybind module compilation here avoids
   # potential warnings or issues from having mixed hidden/non-hidden types.
   set_target_properties(${target_name} PROPERTIES CXX_VISIBILITY_PRESET "hidden")
+  set_target_properties(${target_name} PROPERTIES CUDA_VISIBILITY_PRESET "hidden")
 
   if(WIN32 OR CYGWIN)
     # Link against the Python shared library on Windows
@@ -208,6 +209,15 @@ function(pybind11_add_module target_name)
   if(MSVC)
     # /MP enables multithreaded builds (relevant when there are many files), /bigobj is
     # needed for bigger binding projects due to the limit to 64k addressable sections
-    target_compile_options(${target_name} PRIVATE /MP /bigobj)
+    set(msvc_extra_options /MP /bigobj)
+    if(CMAKE_VERSION VERSION_LESS 3.11)
+      target_compile_options(${target_name} PRIVATE ${msvc_extra_options})
+    else()
+      # Only set these options for C++ files.  This is important so that, for
+      # instance, projects that include other types of source files like CUDA
+      # .cu files don't get these options propagated to nvcc since that would
+      # cause the build to fail.
+      target_compile_options(${target_name} PRIVATE $<$<COMPILE_LANGUAGE:CXX>:${msvc_extra_options}>)
+    endif()
   endif()
 endfunction()