FindCUDA: Fix regression under Visual Studio generators

Since commit v3.5.0-rc1~47^2 (FindCUDA: Support special characters in
path, 2016-01-15) our add_custom_command calls use VERBATIM so that
CMake will automatically quote special characters correctly.  However,
this breaks the special `$(VCInstallDir)` placeholder used with Visual
Studio generators.  Since we do not support preservation of such
placeholders with VERBATIM (see issue #15001) we must fall back to not
using VERBATIM when the placeholder is used.

A better fix would be to stop using `$(VCInstallDir)` and use the value
of `CMAKE_${CUDA_C_OR_CXX}_COMPILER` instead, but that will require
additional semantic and documentation changes.  For now simply fix the
regression with the above approach.

Reported-by: Stephen Sorley <[email protected]>

Modules/FindCUDA.cmake

@@ -1456,6 +1456,11 @@ macro(CUDA_WRAP_SRCS cuda_target format generated_files)
         set(cuda_build_comment_string "Building NVCC (${cuda_build_type}) object ${generated_file_relative_path}")
       endif()
 
+      set(_verbatim VERBATIM)
+      if(ccbin_flags MATCHES "\\$\\(VCInstallDir\\)")
+        set(_verbatim "")
+      endif()
+
       # Build the generated file and dependency file ##########################
       add_custom_command(
         OUTPUT ${generated_file}
@@ -1474,7 +1479,7 @@ macro(CUDA_WRAP_SRCS cuda_target format generated_files)
           -P "${custom_target_script}"
         WORKING_DIRECTORY "${cuda_compile_intermediate_directory}"
         COMMENT "${cuda_build_comment_string}"
-        VERBATIM
+        ${_verbatim}
         )
 
       # Make sure the build system knows the file is generated.
@@ -1586,6 +1591,11 @@ function(CUDA_LINK_SEPARABLE_COMPILATION_OBJECTS output_file cuda_target options
       set(do_obj_build_rule FALSE)
     endif()
 
+    set(_verbatim VERBATIM)
+    if(nvcc_flags MATCHES "\\$\\(VCInstallDir\\)")
+      set(_verbatim "")
+    endif()
+
     if (do_obj_build_rule)
       add_custom_command(
         OUTPUT ${output_file}
@@ -1593,7 +1603,7 @@ function(CUDA_LINK_SEPARABLE_COMPILATION_OBJECTS output_file cuda_target options
         COMMAND ${CUDA_NVCC_EXECUTABLE} ${nvcc_flags} -dlink ${object_files} -o ${output_file}
         ${flags}
         COMMENT "Building NVCC intermediate link file ${output_file_relative_path}"
-        VERBATIM
+        ${_verbatim}
         )
     else()
       get_filename_component(output_file_dir "${output_file}" DIRECTORY)
@@ -1603,7 +1613,7 @@ function(CUDA_LINK_SEPARABLE_COMPILATION_OBJECTS output_file cuda_target options
         COMMAND ${CMAKE_COMMAND} -E echo "Building NVCC intermediate link file ${output_file_relative_path}"
         COMMAND ${CMAKE_COMMAND} -E make_directory "${output_file_dir}"
         COMMAND ${CUDA_NVCC_EXECUTABLE} ${nvcc_flags} ${flags} -dlink ${object_files} -o "${output_file}"
-        VERBATIM
+        ${_verbatim}
         )
     endif()
  endif()