configure: remove check for if_nametoindex

if_nametoindex is present in both POSIX and Windows (since Vista)

+ print the error message as error_msg - debug_msg there was rather a mistake

configure.ac

@@ -299,23 +299,6 @@ AC_DEFUN([DEFINE_CUDA], [
         ])
 AC_SUBST(DLL_LIBS)
 
-if test $system = Windows
-then
-        AC_MSG_CHECKING([if_nametoindex])
-        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-                           #include <windows.h>
-                           #include <iphlpapi.h>
-                           ]], [[
-                                if_nametoindex("eth");]]
-                           )], HAVE_IF_NAMETOINDEX=yes, HAVE_IF_NAMETOINDEX=no)
-        AC_MSG_RESULT([$HAVE_IF_NAMETOINDEX])
-        if test $HAVE_IF_NAMETOINDEX = yes; then
-                AC_DEFINE([HAVE_IF_TONAMEINDEX], 1, [Function if_nametoindex is present.])
-        fi
-else
-        AC_CHECK_FUNCS(if_nametoindex)
-fi
-
 AC_CHECK_FUNCS(usleep)
 AC_CHECK_FUNCS(strtok_r)
 AC_CHECK_FUNCS(timespec_get)

src/rtp/net_udp.c

@@ -810,14 +810,10 @@ socket_udp *udp_init_if(const char *addr, const char *iface, uint16_t rx_port,
                 goto error;
         }
         if (iface != NULL) {
-#ifdef HAVE_IF_NAMETOINDEX
                 if ((s->ifindex = if_nametoindex(iface)) == 0) {
-                        debug_msg("Illegal interface specification\n");
+                        error_msg("Illegal interface specification\n");
                         goto error;
                 }
-#else
-                log_msg(LOG_LEVEL_ERROR, "Cannot set interface name, if_nametoindex not supported.\n");
-#endif
         } else {
                 s->ifindex = 0;
         }