COMP: Fix local variable naming in ctkMacroBuildLibWrapper

Rename my_EXTRA_Python3_LIBRARIES back to my_EXTRA_PYTHON_LIBRARIES.
This is a local variable (not a CMake module output), so using the
Python3_ prefix creates confusion about whether it comes from
FindPython3. The local naming convention uses PYTHON (uppercase).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hjmjohnson

CMake/ctkMacroBuildLibWrapper.cmake

@@ -96,7 +96,7 @@ macro(ctkMacroBuildLibWrapper)
   # these ones to avoid complaints of MSVC
   # Note: "LINK_DIRECTORIES" has to be invoked before "ADD_LIBRARY"
   ctkFunctionExtractOptimizedLibrary(Python3_LIBRARIES PYTHON_LIBRARY)
-  set(my_EXTRA_Python3_LIBRARIES ${PYTHON_LIBRARY} ${PYTHONQT_LIBRARIES})
+  set(my_EXTRA_PYTHON_LIBRARIES ${PYTHON_LIBRARY} ${PYTHONQT_LIBRARIES})
 
   # Does a header having the expected filename exists ?
   string(REGEX REPLACE "^CTK" "ctk" lib_name_lc_ctk ${lib_name})
@@ -122,7 +122,7 @@ macro(ctkMacroBuildLibWrapper)
     list(APPEND KIT_PYTHONQT_SRCS ${DECORATOR_HEADER})
   endif()
   add_library(${lib_name}PythonQt ${MY_WRAPPER_LIBRARY_TYPE} ${KIT_PYTHONQT_SRCS})
-  target_link_libraries(${lib_name}PythonQt ${lib_name} ${my_EXTRA_Python3_LIBRARIES})
+  target_link_libraries(${lib_name}PythonQt ${lib_name} ${my_EXTRA_PYTHON_LIBRARIES})
   if(MY_WRAPPER_LIBRARY_TYPE STREQUAL "STATIC")
     if(CMAKE_SIZEOF_VOID_P EQUAL 8) # 64-bit
       set_target_properties(${lib_name}PythonQt PROPERTIES COMPILE_FLAGS "-fPIC")