link against required libraries
include sys/fcntl.h for F_[SG]ET constants
don't try to use an undefined constant

--- api/libsphinxclient/configure.in
+++ api/libsphinxclient/configure.in
@@ -33,6 +33,9 @@
 dnl Checks for header files.
 AC_CHECK_HEADERS(string.h strings.h unistd.h stdint.h)
 
+AC_CHECK_LIB([nsl], gethostbyname)
+AC_CHECK_LIB([socket], connect)
+
 DEFAULT_INSTALL_PREFIX="/usr/local"
 
 AC_ARG_ENABLE(debug,
--- api/libsphinxclient/sphinxclient.c
+++ api/libsphinxclient/sphinxclient.c
@@ -57,6 +57,7 @@
 	#include <netdb.h>
 	#include <errno.h>
 	#include <sys/un.h>
+	#include <sys/fcntl.h>
 #endif
 
 //////////////////////////////////////////////////////////////////////////
@@ -1280,7 +1281,7 @@
 static sphinx_bool net_write ( int fd, const char * bytes, int len, sphinx_client * client )
 {
 	int res;
-#if defined(_WIN32) || defined(SO_NOSIGPIPE)
+#if defined(_WIN32) || defined(SO_NOSIGPIPE) || !defined(MSG_NOSIGNAL)
 	res = send ( fd, bytes, len, 0 );
 #else
 	res = send ( fd, bytes, len, MSG_NOSIGNAL );