Undefined macro?

[GFdevelop]

make fail with VDE_ETHBUFSIZE undeclared...where is defined?

make  all-am
make[1]: ingresso nella directory "/home/gabriele/mytmp/vdens/src/vdens"
gcc -DHAVE_CONFIG_H -I.   -D_FORTIFY_SOURCE=2  -march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong -fno-plt -MT vdens.o -MD -MP -MF .deps/vdens.Tpo -c -o vdens.o vdens.c
vdens.c: In function ‘plug2tap’:
vdens.c:214:12: error: ‘VDE_ETHBUFSIZE’ undeclared (first use in this function); did you mean ‘FD_SETSIZE’?
   char buf[VDE_ETHBUFSIZE];
            ^~~~~~~~~~~~~~
            FD_SETSIZE
vdens.c:214:12: note: each undeclared identifier is reported only once for each function it appears in
vdens.c: In function ‘stream2tap’:
vdens.c:258:20: error: ‘VDE_ETHBUFSIZE’ undeclared (first use in this function); did you mean ‘FD_SETSIZE’?
  unsigned char buf[VDE_ETHBUFSIZE];
                    ^~~~~~~~~~~~~~
                    FD_SETSIZE
vdens.c: In function ‘mountaddr’:
vdens.c:299:3: warning: ignoring return value of ‘asprintf’, declared with attribute warn_unused_result [-Wunused-result]
   asprintf(&line, "nameserver %*.*s\n", len, len, tagbegin);
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vdens.c:300:3: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
   write(fd, line, strlen(line));
   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vdens.c: In function ‘unsharenet’:
vdens.c:144:4: warning: ignoring return value of ‘read’, declared with attribute warn_unused_result [-Wunused-result]
    read(pipe_fd[0], &unshare_rv, sizeof(unshare_rv));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vdens.c:151:4: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
    write(pipe_fd[1], &unshare_rv, sizeof(unshare_rv));
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
make[1]: *** [Makefile:413: vdens.o] Error 1
make[1]: uscita dalla directory "/home/gabriele/mytmp/vdens/src/vdens"
make: *** [Makefile:305: all] Error 2

[Renzo Davoli]

vdens requires vdeplug4.

You are right, it wasn't clear.
I have added an explicit note in README.md
Thank you.