Always install all device headers even when device isn't enabled.

vtkm_declare_headers now is able to not test headers, by using the
TESTABLE keyword.

CMake/VTKmMacros.cmake

@@ -153,17 +153,26 @@ endfunction(vtkm_requires_thrust_to_test)
 # compiled and show up in an IDE.
 function(vtkm_declare_headers)
   set(options CUDA)
-  set(oneValueArgs)
+  set(oneValueArgs TESTABLE)
   set(multiValueArgs)
   cmake_parse_arguments(VTKm_DH "${options}"
     "${oneValueArgs}" "${multiValueArgs}"
     ${ARGN}
     )
+
+  #The testable keyword allows the caller to turn off the header testing,
+  #mainly used so that backends can be installed even when they can't be
+  #built on the machine.
+  #Since this is an optional property not setting it means you do want testing
+  if(NOT DEFINED VTKm_DH_TESTABLE)
+      set(VTKm_DH_TESTABLE ON)
+  endif()
+
   set(hfiles ${VTKm_DH_UNPARSED_ARGUMENTS})
   vtkm_get_kit_name(name dir_prefix)
 
   #only do header testing if enable testing is turned on
-  if (VTKm_ENABLE_TESTING)
+  if (VTKm_ENABLE_TESTING AND VTKm_DH_TESTABLE)
     vtkm_add_header_build_test(
       "${name}" "${dir_prefix}" "${VTKm_DH_CUDA}" ${hfiles})
   endif()

vtkm/cont/CMakeLists.txt

@@ -68,12 +68,8 @@ add_subdirectory(arg)
 
 vtkm_declare_headers(${impl_headers} ${headers})
 
-if (VTKm_ENABLE_CUDA)
-  add_subdirectory(cuda)
-endif ()
-if (VTKm_ENABLE_TBB)
-  add_subdirectory(tbb)
-endif ()
+add_subdirectory(cuda)
+add_subdirectory(tbb)
 
 #-----------------------------------------------------------------------------
 add_subdirectory(testing)

vtkm/cont/cuda/CMakeLists.txt

@@ -23,14 +23,18 @@ set(headers
   DeviceAdapterCuda.h
   )
 
-vtkm_disable_troublesome_thrust_warnings()
+#-----------------------------------------------------------------------------
+if (VTKm_ENABLE_CUDA)
+  vtkm_disable_troublesome_thrust_warnings()
+  CUDA_INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
+endif()
 
 #-----------------------------------------------------------------------------
-CUDA_INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
-
 add_subdirectory(internal)
+vtkm_declare_headers(CUDA ${headers} TESTABLE ${VTKm_ENABLE_CUDA})
 
 #-----------------------------------------------------------------------------
-vtkm_declare_headers(CUDA ${headers})
+if (VTKm_ENABLE_CUDA)
+  add_subdirectory(testing)
+endif()
 
-add_subdirectory(testing)

vtkm/cont/cuda/internal/CMakeLists.txt

@@ -28,6 +28,9 @@ set(headers
   ThrustExceptionHandler.h
   )
 
-vtkm_declare_headers(CUDA ${headers})
+vtkm_declare_headers(CUDA ${headers} TESTABLE ${VTKm_ENABLE_CUDA})
 
-add_subdirectory(testing)
+#-----------------------------------------------------------------------------
+if (VTKm_ENABLE_CUDA)
+  add_subdirectory(testing)
+endif()

vtkm/cont/tbb/CMakeLists.txt

@@ -24,6 +24,9 @@ set(headers
 
 add_subdirectory(internal)
 
-vtkm_declare_headers(${headers})
+vtkm_declare_headers(${headers} TESTABLE ${VTKm_ENABLE_TBB})
 
-add_subdirectory(testing)
+#-----------------------------------------------------------------------------
+if (VTKm_ENABLE_TBB)
+  add_subdirectory(testing)
+endif()

vtkm/cont/tbb/internal/CMakeLists.txt

@@ -31,4 +31,4 @@ if("${TBB_VERSION_MAJOR}.${TBB_VERSION_MINOR}" VERSION_LESS 4.3)
   set(headers ${headers} parallel_sort.h)
 endif()
 
-vtkm_declare_headers(${headers})
+vtkm_declare_headers(${headers} TESTABLE ${VTKm_ENABLE_TBB})

vtkm/exec/CMakeLists.txt

@@ -39,9 +39,7 @@ vtkm_declare_headers(${impl_headers} ${headers})
 
 
 #-----------------------------------------------------------------------------
-if (VTKm_ENABLE_CUDA)
-  add_subdirectory(cuda)
-endif ()
+add_subdirectory(cuda)
 
 
 #-----------------------------------------------------------------------------

vtkm/exec/cuda/CMakeLists.txt

@@ -18,14 +18,5 @@
 ##  this software.
 ##============================================================================
 
-set(headers
-  )
-
 #-----------------------------------------------------------------------------
 add_subdirectory(internal)
-
-# vtkm_declare_headers(${impl_headers} ${headers})
-
-
-#-----------------------------------------------------------------------------
-# add_subdirectory(testing)

vtkm/exec/cuda/internal/CMakeLists.txt

@@ -24,13 +24,10 @@ set(headers
   WrappedOperators.h
   )
 
-vtkm_disable_troublesome_thrust_warnings()
-
 #-----------------------------------------------------------------------------
-CUDA_INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
+if (VTKm_ENABLE_CUDA)
+  vtkm_disable_troublesome_thrust_warnings()
+  CUDA_INCLUDE_DIRECTORIES(${Boost_INCLUDE_DIRS})
+endif()
 
-vtkm_declare_headers(CUDA ${headers})
-
-
-#-----------------------------------------------------------------------------
-# add_subdirectory(testing)
+vtkm_declare_headers(CUDA ${headers} TESTABLE ${VTKm_ENABLE_CUDA})