OpenCL-SDK Fix whereami dependency target

When adding OpenCL-SDK via CPMAddPackage (cmake 3.22.1) as such:

CPMAddPackage(
  NAME OpenCL_SDK
  GIT_TAG v2023.12.14
  GITHUB_REPOSITORY "KhronosGroup/OpenCL-SDK"
  OPTIONS
    "BUILD_TESTING OFF"
    "BUILD_TESTS OFF"
    "BUILD_DOCS OFF"
    "OPENCL_SDK_BUILD_SAMPLES OFF"
    "OPENCL_SDK_TEST_SAMPLES OFF"
    "OPENCL_SDK_BUILD_OPENGL_SAMPLES OFF"
)

the following is issued:

CMake Error at build/_deps/opencl_sdk-src/lib/CMakeLists.txt:23 (add_libr
ary):
  Cannot find source file:

    ##############/proj/build/_deps/opencl_sdk-build/_d
eps/whereami-external-src/src/whereami.c

  Tried extensions .c .C .c++ .cc .cpp .cxx .cu .mpp .m .M .mm .ixx .cppm
 .h
  .hh .h++ .hm .hpp .hxx .in .txx .f .F .for .f77 .f90 .f95 .f03 .hip .is
pc


CMake Error in build/_deps/opencl_sdk-src/lib/CMakeLists.txt:
  Imported target "whereami" includes non-existent path

    "##############/proj/build/_deps/opencl_sdk-build/_
deps/whereami-external-src/src"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
  provide.



CMake Error in build/_deps/opencl_sdk-src/lib/CMakeLists.txt:
  Imported target "whereami" includes non-existent path

    "##############/proj/build/_deps/opencl_sdk-build/_
deps/whereami-external-src/src"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
  provide.

as whereami/whereami.cmake depends on CMAKE_CURRENT_BINARY_DIR for the include/source paths. This change should fix that without side-effects.