diff -Naur firefox-52.9.0esr.orig/ipc/chromium/src/third_party/libevent/arc4random.c firefox-52.9.0esr/ipc/chromium/src/third_party/libevent/arc4random.c
--- firefox-52.9.0esr.orig/ipc/chromium/src/third_party/libevent/arc4random.c	2024-01-07 16:54:39.331683004 +0100
+++ firefox-52.9.0esr/ipc/chromium/src/third_party/libevent/arc4random.c	2024-01-07 19:46:19.624639689 +0100
@@ -477,20 +477,6 @@
 }
 #endif
 
-ARC4RANDOM_EXPORT void
-arc4random_buf(void *_buf, size_t n)
-{
-	unsigned char *buf = _buf;
-	_ARC4_LOCK();
-	arc4_stir_if_needed();
-	while (n--) {
-		if (--arc4_count <= 0)
-			arc4_stir();
-		buf[n] = arc4_getbyte();
-	}
-	_ARC4_UNLOCK();
-}
-
 #ifndef ARC4RANDOM_NOUNIFORM
 /*
  * Calculate a uniformly distributed random number less than upper_bound
diff -Naur firefox-52.9.0esr.orig/ipc/chromium/src/third_party/libevent/linux/event2/event-config.h firefox-52.9.0esr/ipc/chromium/src/third_party/libevent/linux/event2/event-config.h
--- firefox-52.9.0esr.orig/ipc/chromium/src/third_party/libevent/linux/event2/event-config.h	2024-01-07 16:54:39.341683019 +0100
+++ firefox-52.9.0esr/ipc/chromium/src/third_party/libevent/linux/event2/event-config.h	2024-01-07 18:37:36.641265170 +0100
@@ -23,11 +23,15 @@
 /* Define if libevent should not be compiled with thread support */
 /* #undef _EVENT_DISABLE_THREAD_SUPPORT */
 
+#ifdef HAVE_ARC4RANDOM
 /* Define to 1 if you have the `arc4random' function. */
-/* #undef _EVENT_HAVE_ARC4RANDOM */
+#define EVENT__HAVE_ARC4RANDOM 1
+#endif
 
+#ifdef HAVE_ARC4RANDOM_BUF
 /* Define to 1 if you have the `arc4random_buf' function. */
-/* #undef _EVENT_HAVE_ARC4RANDOM_BUF */
+#define EVENT__HAVE_ARC4RANDOM_BUF 1
+#endif
 
 /* Define to 1 if you have the <arpa/inet.h> header file. */
 #define _EVENT_HAVE_ARPA_INET_H 1