[OpenMP] CUDA plugin: add include directory for libelf

[grokos]

Summary

Allow the user to manually specify where libelf resides in case it is not installed to one of the default locations which cmake looks up. The generic-elf-64 plugin already supports that.

Thanks to Marty McFadden for submitting the patch.

[Hahnfeld]

LGTM

openmp/trunk/libomptarget/plugins/cuda/CMakeLists.txt

if(CMAKE_SYSTEM_PROCESSOR MATCHES "(x86_64)|(ppc64le)$" AND CMAKE_SYSTEM_NAME MATCHES "Linux")
       # Define the suffix for the runtime messaging dumps.
       add_definitions(-DTARGET_NAME=CUDA)
     
       if(LIBOMPTARGET_CMAKE_BUILD_TYPE MATCHES debug)
           add_definitions(-DCUDA_ERROR_REPORT)
       endif()
       
       include_directories(${LIBOMPTARGET_DEP_CUDA_INCLUDE_DIRS})
+      include_directories(${LIBOMPTARGET_DEP_LIBELF_INCLUDE_DIRS})
     
       add_library(omptarget.rtl.cuda SHARED src/rtl.cpp)
       
       # Install plugin under the lib destination folder.
       install(TARGETS omptarget.rtl.cuda LIBRARY DESTINATION lib${LIBOMPTARGET_LIBDIR_SUFFIX})
       
       target_link_libraries(omptarget.rtl.cuda 
         ${LIBOMPTARGET_DEP_CUDA_LIBRARIES} 
         cuda 
         ${LIBOMPTARGET_DEP_LIBELF_LIBRARIES}
         "-Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/../exports")
     
       # Report to the parent scope that we are building a plugin for CUDA.
       set(LIBOMPTARGET_SYSTEM_TARGETS "${LIBOMPTARGET_SYSTEM_TARGETS} nvptx64-nvidia-cuda" PARENT_SCOPE)
     else()
       libomptarget_say("Not building CUDA offloading plugin: only support CUDA in Linux x86_64 or ppc64le hosts.")
     endif()
   else()
     libomptarget_say("Not building CUDA offloading plugin: CUDA not found in system.")
   endif()
 else(LIBOMPTARGET_DEP_LIBELF_FOUND)
   libomptarget_say("Not building CUDA offloading plugin: libelf dependency not found.")
-endif(LIBOMPTARGET_DEP_LIBELF_FOUND)
+endif(LIBOMPTARGET_DEP_LIBELF_FOUND)