include cleanups: remove unused headers and add feature test macros

src/network/__ipparse.c

@@ -1,4 +1,3 @@
-#include <string.h>
 #include <stdlib.h>
 #include <ctype.h>
 #include <sys/socket.h>

src/network/gethostbyaddr.c

@@ -1,8 +1,6 @@
 #define _GNU_SOURCE
 
 #include <netdb.h>
-#include <string.h>
-#include <netinet/in.h>
 #include <errno.h>
 #include <stdlib.h>
 

src/network/gethostbyname2.c

@@ -2,8 +2,6 @@
 
 #include <sys/socket.h>
 #include <netdb.h>
-#include <string.h>
-#include <netinet/in.h>
 #include <errno.h>
 #include <stdlib.h>
 

src/network/gethostbyname2_r.c

@@ -5,7 +5,7 @@
 #include <string.h>
 #include <netinet/in.h>
 #include <errno.h>
-#include <inttypes.h>
+#include <stdint.h>
 
 int gethostbyname2_r(const char *name, int af,
 	struct hostent *h, char *buf, size_t buflen,

src/network/getifaddrs.c

@@ -11,6 +11,7 @@
 #include <arpa/inet.h> /* inet_pton */
 #include <unistd.h>
 #include <sys/ioctl.h>
+#include <sys/socket.h>
 
 typedef union {
 	struct sockaddr_in6 v6;

src/network/getnameinfo.c

@@ -1,6 +1,5 @@
 #include <netdb.h>
 #include <limits.h>
-#include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 #include <sys/socket.h>

src/network/if_nameindex.c

@@ -6,8 +6,6 @@
 #include <errno.h>
 #include "syscall.h"
 
-#include <stdio.h>
-
 static void *do_nameindex(int s, size_t n)
 {
 	size_t i, len, k;

src/network/inet_ntop.c

@@ -1,7 +1,5 @@
 #include <sys/socket.h>
-#include <netinet/in.h>
 #include <arpa/inet.h>
-#include <netdb.h>
 #include <errno.h>
 #include <stdio.h>
 #include <string.h>

src/network/proto.c

@@ -1,5 +1,4 @@
 #include <netdb.h>
-#include <stdio.h>
 #include <string.h>
 
 /* do we really need all these?? */

src/network/recv.c

@@ -1,6 +1,4 @@
 #include <sys/socket.h>
-#include "syscall.h"
-#include "libc.h"
 
 ssize_t recv(int fd, void *buf, size_t len, int flags)
 {

src/network/res_query.c

@@ -1,4 +1,5 @@
 #define _GNU_SOURCE
+#include <resolv.h>
 #include <netdb.h>
 #include "__dns.h"
 #include "libc.h"

src/network/send.c

@@ -1,6 +1,4 @@
 #include <sys/socket.h>
-#include "syscall.h"
-#include "libc.h"
 
 ssize_t send(int fd, const void *buf, size_t len, int flags)
 {

src/network/serv.c

@@ -1,6 +1,4 @@
 #include <netdb.h>
-#include <stdio.h>
-#include <string.h>
 
 void endservent(void)
 {