tls: revert commit a08562b2e56c89900220b7ed15c9ccd12655d9a6

- GH#3791: users of tls.so on systems that provide only
  libssl3 (e.g. bookworm) are advised to try >= 5.8.0

src/modules/tls/tls_mod.c

@@ -306,17 +306,6 @@ static tls_domains_cfg_t* tls_use_modparams(void)
 }
 #endif
 
-/* unconditionally perform thread-local clean-up
- * especially needed with libssl3 uses
- * (bookworm/jammy/noble/el9)
- */
-static void fork_child(void)
-{
-    for(int k = 0; k < 16; k++) {
-        if(pthread_getspecific(k) != 0)
-            pthread_setspecific(k, 0x0);
-    }
-}
 
 static int mod_init(void)
 {
@@ -418,9 +407,6 @@ static int mod_init(void)
 	if(sr_tls_event_callback.s == NULL || sr_tls_event_callback.len <= 0) {
 		tls_lookup_event_routes();
 	}
-        /* minimal fix for libssl 1.1.1/3.x uses
-         */
-        pthread_atfork(NULL, NULL, &fork_child);
 	return 0;
 error:
 	tls_h_mod_destroy_f();
@@ -649,6 +635,11 @@ int mod_register(char *path, int *dlflags, void *p1, void *p2)
 
 	register_tls_hooks(&tls_h);
 
+#if OPENSSL_VERSION_NUMBER >= 0x10100000L
+	LM_DBG("setting cryptorand random engine\n");
+	RAND_set_rand_method(RAND_ksr_cryptorand_method());
+#endif
+
 	sr_kemi_modules_add(sr_kemi_tls_exports);
 
 	return 0;