Add CMake SYCL changes to oneDPLConfig.cmake.in

This was copied over directly from CMakeLists.txt and is required
for AdaptiveCPP to be recognized as a SYCL compiler.

cmake/templates/oneDPLConfig.cmake.in

@@ -117,26 +117,29 @@ if (EXISTS "${_onedpl_headers}")
         endif()
 
         # Check SYCL support by the compiler
-        check_cxx_compiler_flag("-fsycl" _fsycl_option)
+        set(FSYCL_OPTION "-fsycl")
+        check_cxx_compiler_flag(${FSYCL_OPTION} _fsycl_option)
         if (_fsycl_option)
-            CHECK_INCLUDE_FILE_CXX("sycl/sycl.hpp" _sycl_header "-fsycl")
-            if (NOT _sycl_header)
-                CHECK_INCLUDE_FILE_CXX("CL/sycl.hpp" _sycl_header_old "-fsycl")
-            endif()
-            if (_sycl_header OR _sycl_header_old)
-                set(_sycl_support TRUE)
-            endif()
+            set(FSYCL_OPTION_IF_SUPPORTED ${FSYCL_OPTION})
+        endif()
+
+        CHECK_INCLUDE_FILE_CXX("sycl/sycl.hpp" SYCL_HEADER ${FSYCL_OPTION_IF_SUPPORTED})
+        if (NOT SYCL_HEADER)
+            CHECK_INCLUDE_FILE_CXX("CL/sycl.hpp" SYCL_HEADER_OLD ${FSYCL_OPTION_IF_SUPPORTED})
+        endif()
+        if (SYCL_HEADER OR SYCL_HEADER_OLD)
+            set(SYCL_SUPPORT TRUE)
         endif()
 
-        if (_sycl_support)
+        if (SYCL_SUPPORT)
             # Enable SYCL* with compilers/compiler drivers not passing -fsycl by default
-            if (NOT CMAKE_CXX_COMPILER MATCHES ".*(dpcpp-cl|dpcpp)(.exe)?$")
-                message(STATUS "Adding -fsycl compiler option")
-                target_compile_options(oneDPL INTERFACE -fsycl)
-                target_link_libraries(oneDPL INTERFACE -fsycl)
+            if (_fsycl_option AND NOT CMAKE_CXX_COMPILER MATCHES ".*(dpcpp-cl|dpcpp)(.exe)?$")
+                message(STATUS "Adding ${FSYCL_OPTION} compiler option")
+                target_compile_options(oneDPL INTERFACE ${FSYCL_OPTION})
+                target_link_libraries(oneDPL INTERFACE ${FSYCL_OPTION})
             endif()
         else()
-            message(STATUS "oneDPL: -fsycl compiler option is not supported or sycl.hpp is not available, set ONEDPL_USE_DPCPP_BACKEND=0")
+            message(STATUS "oneDPL: SYCL is not supported. Set ONEDPL_USE_DPCPP_BACKEND=0")
             set_property(TARGET oneDPL APPEND PROPERTY INTERFACE_COMPILE_DEFINITIONS ONEDPL_USE_DPCPP_BACKEND=0)
         endif()
     endif()