Incompatible assignment of 'const gchar' to 'gchar' in g_utf8_next_char usage

[chenrui333]

👋 while regression building 0.5.5 release, seeing the following build error:

  /tmp/sdcv-20240914-6823-nvt5r0/sdcv-0.5.5/src/stardict_lib.cpp:1050:20: error: cannot initialize a variable of type 'gchar *' (aka 'char *') with an rvalue of type 'const gchar *' (aka 'const char *')
   1050 |             gchar *nextchar = g_utf8_next_char(sWord);
        |                    ^          ~~~~~~~~~~~~~~~~~~~~~~~
  1 error generated.
  make[2]: *** [CMakeFiles/sdcv.dir/src/stardict_lib.cpp.o] Error 1

[bobby285271]

We also experience this on NixOS with GLib 2.82 (https://hydra.nixos.org/build/274413637/nixlog/1), it looks like g_utf8_next_char no longer includes a cast to char* since https://gitlab.gnome.org/GNOME/glib/-/merge_requests/4016.