LD-preloadable library preventing GTK from killing applications using it under Wayland

fix_wl_display_flush.c

/*
  Build with
  
  $ cc -Wall -O2 -fPIC -shared -o libfix_wl_display_flush.so fix_wl_display_flush.c
  
  Use as
  
  $ LD_PRELOAD=libfix_wl_display_flush.so ./app
 */
#define _GNU_SOURCE
#include <dlfcn.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <wayland-client-core.h>

typedef int (*wl_display_flush_t)(struct wl_display*);

int wl_display_flush(struct wl_display* d)
{
    static wl_display_flush_t orig_wl_display_flush = NULL;
    if (!orig_wl_display_flush) {
        orig_wl_display_flush = (wl_display_flush_t)dlsym(RTLD_NEXT, "wl_display_flush");
        if (!orig_wl_display_flush) {
            fprintf(stderr, "Failed to get wl_display_flush(): %s\n", dlerror());
            exit(127);
        }
    }

    int rc = orig_wl_display_flush(d);
    if (rc < 0) {
        if (errno == EAGAIN) {
            usleep(100000);
            rc = orig_wl_display_flush(d);
        }
    }

    return rc;
}