Check for and include <sys/select.h>.

This was reported as a build error by John Spencer using musl libc.
http://seclists.org/nmap-dev/2012/q3/776

nbase/configure

@@ -3685,7 +3685,7 @@ fi
 done
 
 
-for ac_header in string.h getopt.h strings.h sys/param.h sys/time.h unistd.h errno.h sys/types.h sys/socket.h netinet/in.h arpa/inet.h sys/stat.h netdb.h sys/wait.h fcntl.h sys/resource.h inttypes.h mach-o/dyld.h
+for ac_header in string.h getopt.h strings.h sys/param.h sys/time.h unistd.h errno.h sys/select.h sys/types.h sys/socket.h netinet/in.h arpa/inet.h sys/stat.h netdb.h sys/wait.h fcntl.h sys/resource.h inttypes.h mach-o/dyld.h
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"

nbase/configure.ac

@@ -70,7 +70,7 @@ esac
 
 dnl Checks for header files.
 AC_HEADER_STDC
-AC_CHECK_HEADERS( string.h getopt.h strings.h sys/param.h sys/time.h unistd.h errno.h sys/types.h sys/socket.h netinet/in.h arpa/inet.h sys/stat.h netdb.h sys/wait.h fcntl.h sys/resource.h inttypes.h mach-o/dyld.h)
+AC_CHECK_HEADERS( string.h getopt.h strings.h sys/param.h sys/time.h unistd.h errno.h sys/select.h sys/types.h sys/socket.h netinet/in.h arpa/inet.h sys/stat.h netdb.h sys/wait.h fcntl.h sys/resource.h inttypes.h mach-o/dyld.h)
 AC_HEADER_TIME
 dnl A special check required for <net/if.h> on Darwin. See
 dnl http://www.gnu.org/software/autoconf/manual/html_node/Header-Portability.html.

nbase/nbase.h

@@ -149,6 +149,11 @@
 
 #include <stdlib.h>
 #include <ctype.h>
+
+#if HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
 #if HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif

nbase/nbase_config.h.in

@@ -138,6 +138,8 @@
 
 #undef HAVE_SYS_PARAM_H
 
+#undef HAVE_SYS_SELECT_H
+
 #undef HAVE_SYS_SOCKIO_H
 
 #undef HAVE_SYS_SOCKET_H