The 'gcem' submodule directory seems to be empty or incomplete. Attempting to download gcem from Github.
**************************************************************


CMake Warning:
  Manually-specified variables were not used by the project:

    CMAKE_LD_FLAGS
    LIB_SUFFIX


In file included from /var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/synth/fluid_gen.h:24,
                 from /var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/sfloader/fluid_sffile.h:27,
                 from /var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/sfloader/fluid_sffile.c:24:
In function ‘process_info’,
    inlined from ‘load_header’ at /var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/sfloader/fluid_sffile.c:603:9,
    inlined from ‘fluid_sffile_open’ at /var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/sfloader/fluid_sffile.c:405:9:
/var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/utils/fluidsynth_priv.h:328:38: warning: ‘item.chr’ may be used uninitialized [-Wmaybe-uninitialized]
  328 | #define FLUID_LOG                    fluid_log
/var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/sfloader/fluid_sffile.c:876:13: note: in expansion of macro ‘FLUID_LOG’
  876 |             FLUID_LOG(FLUID_DBG, "INFO chunk %c%c%c%c (%d bytes) -> %s", p[0], p[1], p[2], p[3], chunk.size, item.chr);
      |             ^~~~~~~~~
/var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/sfloader/fluid_sffile.c: In function ‘fluid_sffile_open’:
/var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/sfloader/fluid_sffile.c:685:7: note: ‘item.chr’ was declared here
  685 |     } item;
      |       ^~~~
/var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/midi/fluid_midi.c: In function ‘fluid_player_set_bpm’:
/var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/midi/fluid_midi.c:2577:5: warning: ‘fluid_player_set_midi_tempo’ is deprecated [-Wdeprecated-declarations]
 2577 |     return fluid_player_set_midi_tempo(player, 60000000L / bpm);
      |     ^~~~~~
/var/pisi/fluidsynth-2.5.3-9/work/fluidsynth-2.5.3/src/midi/fluid_midi.c:2554:5: note: declared here
 2554 | int fluid_player_set_midi_tempo(fluid_player_t *player, int tempo)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~