fix: better handling of output

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

src/cython_cmake/cmake/UseCython.cmake

@@ -140,11 +140,11 @@ function(Cython_compile_pyx)
   if(NOT CYTHON_OUTPUT)
     get_filename_component(basename "${INPUT}" NAME_WE)
 
-    set(CYTHON_OUPUT "${CMAKE_CURRENT_BINARY_DIR}/${basename}${language_ext}")
+    set(CYTHON_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${basename}${language_ext}")
+  elseif(NOT IS_ABSOLUTE CYTHON_OUTPUT)
+    set(CYTHON_OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${CYTHON_OUTPUT}")
   endif()
 
-  get_filename_component(CYTHON_OUTPUT "${CYTHON_OUPUT}" ABSOLUTE)
-
   # Normalize the input path
   get_filename_component(INPUT "${INPUT}" ABSOLUTE)
   set_source_files_properties("${INPUT}" PROPERTIES GENERATED TRUE)