minor: Fix redefinition warning (closes merbanan#3216)

Author: zuckschwerdt

src/output_rtltcp.c

@@ -79,6 +79,12 @@
 typedef SSIZE_T ssize_t;
 #endif
 
+// _POSIX_HOST_NAME_MAX is broken in gcc-13 at least on MacOS
+#ifndef _POSIX_HOST_NAME_MAX
+//#warning The limits.h include is missing the _POSIX_HOST_NAME_MAX define.
+#define _POSIX_HOST_NAME_MAX 255
+#endif
+
 // MSG_NOSIGNAL is Linux and most BSDs only, not macOS or Windows
 #ifndef MSG_NOSIGNAL
 #define MSG_NOSIGNAL 0

src/output_udp.c

@@ -23,11 +23,6 @@
 #include <errno.h>
 
 #include <limits.h>
-// _POSIX_HOST_NAME_MAX is broken in gcc-13 at least on MacOS
-#ifndef _POSIX_HOST_NAME_MAX
-//#warning The limits.h include is missing the _POSIX_HOST_NAME_MAX define.
-#define _POSIX_HOST_NAME_MAX 255
-#endif
 // gethostname() needs _XOPEN_SOURCE 500 on unistd.h
 #ifndef _XOPEN_SOURCE
 #define _XOPEN_SOURCE 500
@@ -75,6 +70,12 @@
     #define gai_strerror strerror
 #endif
 
+// _POSIX_HOST_NAME_MAX is broken in gcc-13 at least on MacOS
+#ifndef _POSIX_HOST_NAME_MAX
+//#warning The limits.h include is missing the _POSIX_HOST_NAME_MAX define.
+#define _POSIX_HOST_NAME_MAX 255
+#endif
+
 /* Datagram (UDP) client */
 
 typedef struct {