socket.h: add missing include

socket.h uses INET6_ADDRSTRLEN without including arpa/inet.h where it's
defined which might break external users of socket.h

Fix this by adding missing include. The error was introduced in
64b51eb68b

Change-Id: I2883addcb81cec038577e401e356e8f07a947d4c

include/osmocom/core/socket.h

@@ -11,6 +11,13 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+#if (!EMBEDDED)
+#include <arpa/inet.h>
+
+/*! maximum length of a socket name ("r=1.2.3.4:123<->l=5.6.7.8:987") */
+#define OSMO_SOCK_NAME_MAXLEN (2 + INET6_ADDRSTRLEN + 1 + 5 + 3 + 2 + INET6_ADDRSTRLEN + 1 + 5 + 1)
+#endif
+
 struct sockaddr_in;
 struct sockaddr;
 struct osmo_fd;
@@ -28,8 +35,6 @@ struct osmo_fd;
 #define OSMO_SOCK_F_NO_MCAST_ALL  (1 << 4)
 /*! use SO_REUSEADDR on UDP ports (required for multicast) */
 #define OSMO_SOCK_F_UDP_REUSEADDR (1 << 5)
-/*! maximum length of a socket name ("r=1.2.3.4:123<->l=5.6.7.8:987") */
-#define OSMO_SOCK_NAME_MAXLEN (2 + INET6_ADDRSTRLEN + 1 + 5 + 3 + 2 + INET6_ADDRSTRLEN + 1 + 5 + 1)
 
 int osmo_sock_init(uint16_t family, uint16_t type, uint8_t proto,
 		   const char *host, uint16_t port, unsigned int flags);