GPU: Fix standalone compilation without O2 headers

Author: davidrohr

GPU/GPUTracking/Base/cuda/CMakeLists.txt

@@ -197,7 +197,7 @@ if(NOT GPUCA_CUDA_COMPILE_MODE STREQUAL "rdc")
   set_target_properties(${targetName} PROPERTIES LINKER_LANGUAGE CXX)
 endif()
 
-if(NOT ALIGPU_BUILD_TYPE STREQUAL "ALIROOT")
+if(ALIGPU_BUILD_TYPE STREQUAL "O2" OR CONFIG_O2_EXTENSIONS)
   add_library(GPUTrackingCUDAExternalProvider OBJECT GPUReconstructionCUDAExternalProvider.cu)
   add_library(O2::GPUTrackingCUDAExternalProvider ALIAS GPUTrackingCUDAExternalProvider)
   set_property(TARGET GPUTrackingCUDAExternalProvider PROPERTY CUDA_SEPARABLE_COMPILATION ON)

GPU/GPUTracking/Base/hip/CMakeLists.txt

@@ -260,7 +260,7 @@ if(NOT GPUCA_HIP_COMPILE_MODE STREQUAL "rdc")
   target_link_options(${targetName} PRIVATE $<$<COMPILE_LANGUAGE:HIP>:-fno-gpu-rdc>)
 endif()
 
-if(NOT ALIGPU_BUILD_TYPE STREQUAL "ALIROOT")
+if(ALIGPU_BUILD_TYPE STREQUAL "O2" OR CONFIG_O2_EXTENSIONS)
   add_library(GPUTrackingHIPExternalProvider OBJECT ${GPUCA_HIP_SOURCE_DIR}/GPUReconstructionHIPExternalProvider.hip)
   add_library(O2::GPUTrackingHIPExternalProvider ALIAS GPUTrackingHIPExternalProvider)
   target_compile_options(GPUTrackingHIPExternalProvider PRIVATE $<$<COMPILE_LANGUAGE:HIP>:-fgpu-rdc>)

GPU/GPUTracking/cmake/kernel_helpers.cmake

@@ -83,6 +83,7 @@ function(o2_gpu_add_kernel kernel_name kernel_files kernel_bounds kernel_type)
   endif()
   list(APPEND O2_GPU_KERNEL_TEMPLATE_FILES "${TMP_KERNEL_CLASS_FILE}.cxx")
   list(REMOVE_DUPLICATES O2_GPU_KERNEL_TEMPLATE_FILES)
+  list(FILTER O2_GPU_KERNEL_TEMPLATE_FILES EXCLUDE REGEX "^-$")
   list(TRANSFORM O2_GPU_KERNEL_TEMPLATE_FILES APPEND "\"")
   list(TRANSFORM O2_GPU_KERNEL_TEMPLATE_FILES PREPEND "#include \"")
   list(JOIN O2_GPU_KERNEL_TEMPLATE_FILES "\n" O2_GPU_KERNEL_TEMPLATE_FILES)