Compilation Error

Logs:

[8/12] Compiling C object gcm_service.p/mcs_service.c.o
FAILED: gcm_service.p/mcs_service.c.o 
ccache cc -Igcm_service.p -I. -I.. -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/sysprof-6 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -O0 -g -pthread -MD -MQ gcm_service.p/mcs_service.c.o -MF gcm_service.p/mcs_service.c.o.d -o gcm_service.p/mcs_service.c.o -c ../mcs_service.c
../mcs_service.c:220:59: error: initialization of ‘gboolean (*)(GSource *, gboolean (*)(void *), void *)’ {aka ‘int (*)(struct _GSource *, int (*)(void *), void *)’} from incompatible pointer type ‘gboolean (*)(void)’ {aka ‘int (*)(void)’} [-Wincompatible-pointer-types]
  220 | static GSourceFuncs heartbeat_timer_funcs = { .dispatch = heartbeat_timer_callback };
      |                                                           ^~~~~~~~~~~~~~~~~~~~~~~~
../mcs_service.c:220:59: note: (near initialization for ‘heartbeat_timer_funcs.dispatch’)
../mcs_service.c:123:17: note: ‘heartbeat_timer_callback’ declared here
  123 | static gboolean heartbeat_timer_callback()
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~
../mcs_service.c:221:59: error: initialization of ‘gboolean (*)(GSource *, gboolean (*)(void *), void *)’ {aka ‘int (*)(struct _GSource *, int (*)(void *), void *)’} from incompatible pointer type ‘gboolean (*)(void)’ {aka ‘int (*)(void)’} [-Wincompatible-pointer-types]
  221 | static GSourceFuncs reconnect_timer_funcs = { .dispatch = reconnect_timer_callback };
      |                                                           ^~~~~~~~~~~~~~~~~~~~~~~~
../mcs_service.c:221:59: note: (near initialization for ‘reconnect_timer_funcs.dispatch’)
../mcs_service.c:140:17: note: ‘reconnect_timer_callback’ declared here
  140 | static gboolean reconnect_timer_callback()
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~
[11/12] Compiling C object gcm_service.p/register.c.o
ninja: build stopped: subcommand failed.