Ports: Use sendfd()/recvfd() for mm_send_fd()/mm_receive_fd()

Base/etc/passwd

@@ -8,5 +8,6 @@ webcontent:!:15:15:WebContent,,,:/:/bin/false
 image:!:16:16:ImageDecoder,,,:/:/bin/false
 symbol:!:17:17:SymbolServer,,,:/:/bin/false
 websocket:!:18:18:WebSocket,,,:/:/bin/false
+sshd:!:19:19:OpenSSH privsep,,,:/:/bin/false
 anon:!:100:100:Anonymous,,,:/home/anon:/bin/sh
 nona:!:200:200:Nona,,,:/home/nona:/bin/sh

Base/etc/shadow

@@ -9,4 +9,5 @@ webcontent:!*:18727::::::
 image:!*:18727::::::
 symbol:!*:18727::::::
 websocket:!*:18727::::::
+sshd:!*:18727::::::
 nona:!*:18727::::::

Ports/openssh/patches/scm-rights.patch

@@ -0,0 +1,35 @@
+diff -Naur openssh-portable-9ca7e9c861775dd6c6312bc8aaab687403d24676/monitor_fdpass.c openssh-portable-9ca7e9c861775dd6c6312bc8aaab687403d24676.serenity/monitor_fdpass.c
+--- openssh-portable-9ca7e9c861775dd6c6312bc8aaab687403d24676/monitor_fdpass.c	2020-05-27 02:38:00.000000000 +0200
++++ openssh-portable-9ca7e9c861775dd6c6312bc8aaab687403d24676.serenity/monitor_fdpass.c	2021-05-01 12:32:21.145854477 +0200
+@@ -51,6 +51,7 @@
+ int
+ mm_send_fd(int sock, int fd)
+ {
++#ifndef __serenity__
+ #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
+ 	struct msghdr msg;
+ #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
+@@ -107,11 +108,15 @@
+ 	error("%s: file descriptor passing not supported", __func__);
+ 	return -1;
+ #endif
++#else
++    return sendfd(sock, fd);
++#endif
+ }
+ 
+ int
+ mm_receive_fd(int sock)
+ {
++#ifndef __serenity__
+ #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
+ 	struct msghdr msg;
+ #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
+@@ -184,4 +189,7 @@
+ 	error("%s: file descriptor passing not supported", __func__);
+ 	return -1;
+ #endif
++#else
++    return recvfd(sock, 0);
++#endif
+ }