https://bugs.gentoo.org/880381
https://github.com/libevent/libevent/commit/35375101e741d78bf49642c6929c1eb69a7c3d79

From 35375101e741d78bf49642c6929c1eb69a7c3d79 Mon Sep 17 00:00:00 2001
From: Azat Khuzhin <azat@libevent.org>
Date: Fri, 27 Jan 2023 08:57:33 +0100
Subject: [PATCH] Fixes some new warnings under clang-15

- -Wdeprecated-non-prototype

  /src/le/libevent/strlcpy.c:48:1: warning: a function definition without a prototype is deprecated in all versions of C and is not supported in C2x [-Wdeprecated-non-prototype]
  event_strlcpy_(dst, src, siz)

- -Wstrict-prototypes

  /src/le/libevent/evthread.c:82:70: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
  struct evthread_condition_callbacks *evthread_get_condition_callbacks()

- -Wunused-but-set-variable

  /src/le/libevent/test/regress_buffer.c:130:6: warning: variable 'n' set but not used [-Wunused-but-set-variable]
          int n = 0;
                                                                     ^
---
 evthread.c            | 4 ++--
 strlcpy.c             | 6 +-----
 test/regress_buffer.c | 5 -----
 3 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/evthread.c b/evthread.c
index 3eac594d64..c2da914da1 100644
--- a/evthread.c
+++ b/evthread.c
@@ -74,12 +74,12 @@ evthread_set_id_callback(unsigned long (*id_fn)(void))
 	evthread_id_fn_ = id_fn;
 }
 
-struct evthread_lock_callbacks *evthread_get_lock_callbacks()
+struct evthread_lock_callbacks *evthread_get_lock_callbacks(void)
 {
 	return evthread_lock_debugging_enabled_
 	    ? &original_lock_fns_ : &evthread_lock_fns_;
 }
-struct evthread_condition_callbacks *evthread_get_condition_callbacks()
+struct evthread_condition_callbacks *evthread_get_condition_callbacks(void)
 {
 	return evthread_lock_debugging_enabled_
 	    ? &original_cond_fns_ : &evthread_cond_fns_;
diff --git a/strlcpy.c b/strlcpy.c
index 3876475f5a..04c74298dc 100644
--- a/strlcpy.c
+++ b/strlcpy.c
@@ -44,11 +44,7 @@ static char *rcsid = "$OpenBSD: strlcpy.c,v 1.5 2001/05/13 15:40:16 deraadt Exp
  * will be copied.  Always NUL terminates (unless siz == 0).
  * Returns strlen(src); if retval >= siz, truncation occurred.
  */
-size_t
-event_strlcpy_(dst, src, siz)
-	char *dst;
-	const char *src;
-	size_t siz;
+size_t event_strlcpy_(char *dst, const char *src, size_t siz)
 {
 	register char *d = dst;
 	register const char *s = src;
diff --git a/test/regress_buffer.c b/test/regress_buffer.c
index 5683810e26..b0a9e0c162 100644
--- a/test/regress_buffer.c
+++ b/test/regress_buffer.c
@@ -127,19 +127,16 @@ evbuffer_get_waste(struct evbuffer *buf, size_t *allocatedp, size_t *wastedp, si
 {
 	struct evbuffer_chain *chain;
 	size_t a, w, u;
-	int n = 0;
 	u = a = w = 0;
 
 	chain = buf->first;
 	/* skip empty at start */
 	while (chain && chain->off==0) {
-		++n;
 		a += chain->buffer_len;
 		chain = chain->next;
 	}
 	/* first nonempty chain: stuff at the end only is wasted. */
 	if (chain) {
-		++n;
 		a += chain->buffer_len;
 		u += chain->off;
 		if (chain->next && chain->next->off)
@@ -148,7 +145,6 @@ evbuffer_get_waste(struct evbuffer *buf, size_t *allocatedp, size_t *wastedp, si
 	}
 	/* subsequent nonempty chains */
 	while (chain && chain->off) {
-		++n;
 		a += chain->buffer_len;
 		w += (size_t)chain->misalign;
 		u += chain->off;
@@ -158,7 +154,6 @@ evbuffer_get_waste(struct evbuffer *buf, size_t *allocatedp, size_t *wastedp, si
 	}
 	/* subsequent empty chains */
 	while (chain) {
-		++n;
 		a += chain->buffer_len;
 	}
 	*allocatedp = a;