Need to set SYCL_EXT_ONEAPI_COMPLEX on all files from elementwise folder

Author: oleksandr-pavlyk

Diff for: dpctl/tensor/CMakeLists.txt

@@ -183,10 +183,14 @@ if (UNIX)
 else()
   set(_compiler_definitions "SYCL_EXT_ONEAPI_COMPLEX")
 endif()
-set_source_files_properties(
-    ${CMAKE_CURRENT_SOURCE_DIR}/libtensor/source/elementwise_functions.cpp
-    PROPERTIES COMPILE_DEFINITIONS "${_compiler_definitions}"
-)
+foreach(_src_fn ${_elementwise_sources})
+  get_source_file_property(_cmpl_options_defs ${_src_fn} COMPILE_DEFINITIONS)
+  set(_combined_options_defs ${_cmpl_options_defs} "${_compiler_definitions}")
+  set_source_files_properties(
+     ${_src_fn}
+     PROPERTIES COMPILE_DEFINITIONS "${_combined_options_defs}"
+  )
+endforeach()
 
 target_compile_options(${python_module_name} PRIVATE -fno-sycl-id-queries-fit-in-int)
 target_link_options(${python_module_name} PRIVATE -fsycl-device-code-split=per_kernel)