sysklogd: fix building against musl

taking guidance from alpine linux's patch[1], removed a few ifdefs and
fixed up some includes.

[1]: https://git.alpinelinux.org/aports/tree/main/sysklogd/fix-includes.patch

pkgs/os-specific/linux/sysklogd/default.nix

@@ -8,7 +8,7 @@ stdenv.mkDerivation {
     sha256 = "00f2wy6f0qng7qzga4iicyzl9j8b7mp6mrpfky5jxj93ms2w2rji";
   };
 
-  patches = [ ./systemd.patch ./union-wait.patch ];
+  patches = [ ./systemd.patch ./union-wait.patch ./fix-includes.patch ];
 
   NIX_CFLAGS_COMPILE = "-DSYSV";
 

pkgs/os-specific/linux/sysklogd/fix-includes.patch

@@ -0,0 +1,118 @@
+diff -u sysklogd-1.5.1.orig/klogd.c sysklogd-1.5.1/klogd.c
+--- sysklogd-1.5.1.orig/klogd.c	2014-10-04 15:47:18.000000000 -0400
++++ sysklogd-1.5.1/klogd.c	2021-01-18 23:09:23.000000000 -0500
+@@ -260,11 +260,8 @@
+ #include <unistd.h>
+ #include <signal.h>
+ #include <errno.h>
+-#include <sys/fcntl.h>
++#include <fcntl.h>
+ #include <sys/stat.h>
+-#if !defined(__GLIBC__)
+-#include <linux/time.h>
+-#endif /* __GLIBC__ */
+ #include <stdarg.h>
+ #include <paths.h>
+ #include <stdlib.h>
+@@ -277,13 +274,8 @@
+ 
+ #define __LIBRARY__
+ #include <linux/unistd.h>
+-#if !defined(__GLIBC__)
+-# define __NR_ksyslog __NR_syslog
+-_syscall3(int,ksyslog,int, type, char *, buf, int, len);
+-#else
+ #include <sys/klog.h>
+ #define ksyslog klogctl
+-#endif
+ 
+ #define LOG_BUFFER_SIZE 4096
+ #define LOG_LINE_LENGTH 1000
+diff -u sysklogd-1.5.1.orig/ksym_mod.c sysklogd-1.5.1/ksym_mod.c
+--- sysklogd-1.5.1.orig/ksym_mod.c	2014-10-04 15:47:18.000000000 -0400
++++ sysklogd-1.5.1/ksym_mod.c	2021-01-18 23:09:57.000000000 -0500
+@@ -113,12 +113,9 @@
+ #include <unistd.h>
+ #include <signal.h>
+ #include <errno.h>
+-#include <sys/fcntl.h>
++#include <fcntl.h>
+ #include <sys/stat.h>
+ #include "module.h"
+-#if !defined(__GLIBC__)
+-#include <linux/time.h>
+-#endif /* __GLIBC__ */
+ #include <stdarg.h>
+ #include <paths.h>
+ #include <linux/version.h>
+diff -u sysklogd-1.5.1.orig/pidfile.c sysklogd-1.5.1/pidfile.c
+--- sysklogd-1.5.1.orig/pidfile.c	2014-10-04 15:47:18.000000000 -0400
++++ sysklogd-1.5.1/pidfile.c	2021-01-18 23:23:55.000000000 -0500
+@@ -25,6 +25,7 @@
+  */
+ 
+ #include <stdio.h>
++#include <fcntl.h>
+ #include <unistd.h>
+ #include <sys/stat.h>
+ #include <sys/file.h>
+diff -u sysklogd-1.5.1.orig/syslog.c sysklogd-1.5.1/syslog.c
+--- sysklogd-1.5.1.orig/syslog.c	2014-10-04 15:47:18.000000000 -0400
++++ sysklogd-1.5.1/syslog.c	2021-01-18 23:11:45.000000000 -0500
+@@ -55,7 +55,6 @@
+ #include <sys/types.h>
+ #include <sys/socket.h>
+ #include <sys/file.h>
+-#include <sys/signal.h>
+ #include <sys/syslog.h>
+ #if 0
+ #include "syslog.h"
+@@ -64,6 +63,8 @@
+ 
+ #include <sys/uio.h>
+ #include <sys/wait.h>
++#include <signal.h>
++#include <fcntl.h>
+ #include <netdb.h>
+ #include <string.h>
+ #include <time.h>
+diff -u sysklogd-1.5.1.orig/syslogd.c sysklogd-1.5.1/syslogd.c
+--- sysklogd-1.5.1.orig/syslogd.c	2014-10-04 15:47:18.000000000 -0400
++++ sysklogd-1.5.1/syslogd.c	2021-01-18 23:13:25.000000000 -0500
+@@ -519,9 +519,9 @@
+ #include <time.h>
+ 
+ #define SYSLOG_NAMES
++#include <errno.h>
+ #include <sys/syslog.h>
+ #include <sys/param.h>
+-#include <sys/errno.h>
+ #include <sys/ioctl.h>
+ #include <sys/stat.h>
+ #include <sys/wait.h>
+@@ -818,9 +818,7 @@
+ void init();
+ void cfline(char *line, register struct filed *f);
+ int decode(char *name, struct code *codetab);
+-#if defined(__GLIBC__)
+ #define dprintf mydprintf
+-#endif /* __GLIBC__ */
+ static void dprintf(char *, ...);
+ static void allocate_log(void);
+ void sighup_handler();
+@@ -840,15 +838,9 @@
+ 	register char *p;
+ #ifndef TESTING
+ 	ssize_t msglen;
+-#endif
+-#if !defined(__GLIBC__)
+-	int len, num_fds;
+-#else /* __GLIBC__ */
+-#ifndef TESTING
+ 	socklen_t len;
+ #endif
+ 	int num_fds;
+-#endif /* __GLIBC__ */
+ 	/*
+ 	 * It took me quite some time to figure out how this is
+ 	 * supposed to work so I guess I should better write it down.

pkgs/os-specific/linux/sysklogd/systemd.patch

@@ -71,9 +71,9 @@ diff -ruN -x '*~' sysklogd-1.5-old/sd-daemon.c sysklogd-1.5/sd-daemon.c
 +#include <sys/stat.h>
 +#include <sys/socket.h>
 +#include <sys/un.h>
-+#include <sys/fcntl.h>
 +#include <netinet/in.h>
 +#include <stdlib.h>
++#include <fcntl.h>
 +#include <errno.h>
 +#include <unistd.h>
 +#include <string.h>