sys-apps/systemd: add v256.5 with musl libc patches

- https://code.atwilcox.tech/sphen/scaly/systemd
- https://catfox.life/2024/09/05/porting-systemd-to-musl-libc-powered-linux/

sys-apps/systemd/files/0025-man-Ensure-notify-example-includes-string.h.patch

@@ -0,0 +1,31 @@
+From 0bd6d30dc195911d525877b42f4821355f2f25e4 Mon Sep 17 00:00:00 2001
+From: "A. Wilcox" <AWilcox@Wilcox-Tech.com>
+Date: Sun, 18 Aug 2024 03:12:46 -0500
+Subject: [PATCH 25/34] man: Ensure notify example includes <string.h>
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 8bit
+
+This ensures that memcpy and strerror are defined.  This is especially
+important as GCC 14 makes implicit function declarations an error.
+
+Signed-off-by: A. Wilcox <AWilcox@Wilcox-Tech.com>
+Signed-off-by: Alexander Miroshnichenko <alex@millerson.name>
+---
+ man/notify-selfcontained-example.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/man/notify-selfcontained-example.c b/man/notify-selfcontained-example.c
+index 6bbe4f2e3bad..3498d508430d 100644
+--- a/man/notify-selfcontained-example.c
++++ b/man/notify-selfcontained-example.c
+@@ -15,6 +15,7 @@
+ #include <stddef.h>
+ #include <stdlib.h>
+ #include <stdio.h>
++#include <string.h>
+ #include <sys/socket.h>
+ #include <sys/un.h>
+ #include <time.h>
+-- 
+2.41.0
+