feat: enable MODMESH_USE_PYSIDE to on, by default

refactor: remove the switch

refactor: comments

refactor: update the comment for the PySide6

Change the comment line and remove msg

Author: Telomelonia

CMakeLists.txt

@@ -138,6 +138,8 @@ set(MODMESH_INCLUDE_DIR "${CMAKE_CURRENT_LIST_DIR}/cpp" CACHE INTERNAL "")
 
 include_directories(${MODMESH_INCLUDE_DIR})
 
+# PySide6 is required since 2023 (see issue https://github.com/solvcon/modmesh/issues/220)
+add_compile_definitions(MODMESH_USE_PYSIDE)
 execute_process(
     COMMAND python3 -c "import sys, os, PySide6; sys.stdout.write(os.path.dirname(PySide6.__file__))"
     OUTPUT_VARIABLE PYSIDE6_PYTHON_PACKAGE_PATH

cpp/modmesh/pilot/wrap_pilot.cpp

@@ -36,7 +36,7 @@
 #include <QClipboard>
 #include <QMenu>
 
-// Usually MODMESH_PYSIDE6_FULL is not defined unless for debugging.
+// PySide6 is required since 2023 (see issue https://github.com/solvcon/modmesh/issues/220)
 #ifdef MODMESH_PYSIDE6_FULL
 #include <pyside.h>
 #else // MODMESH_PYSIDE6_FULL