Implementing VMime in qt project

Hello everyone, so I've been struggling for days now trying to achieve this mission impossible, due to my lack of experience with qt. So I have to build an application where the user of the application is able to send emails from the application to a gmail account, I was able to do that using smtp, however, I'd like to send a button or link in that email where the receiver is able to click it to confirm something, and when he does, the user of the application is notified without logging in to gmail. I've done some research, I found a library VMime, but I got stuck trying to follow this tuto http://web.archive.org/web/201512012....omgwtfbbq.nl/ , cause when I run make with libgpg-error I get

Quote:

$ make
make all-recursive
make[1]: Entering directory `/usr/home/usr/libgpg-error-1.27'
Making all in m4
make[2]: Entering directory `/usr/home/usr/libgpg-error-1.27/m4'
make[2]: Nothing to be done for `all'.
make[2]: Leaving directory `/usr/home/usr/libgpg-error-1.27/m4'
Making all in src
make[2]: Entering directory `/usr/home/usr/libgpg-error-1.27/src'
make all-am
make[3]: Entering directory `/usr/home/usr/libgpg-error-1.27/src'
/bin/sh ../libtool --tag=CC --mode=compile gcc -DHAVE_CONFIG_H -I. -I.. -DLOCALEDIR=\"/mingw/share/locale\" -I/mingw/include -g -O2 -Wall -Wpointer-arith -Wno-psabi -MT libgpg_error_la-w32-estream.lo -MD -MP -MF .deps/libgpg_error_la-w32-estream.Tpo -c -o libgpg_error_la-w32-estream.lo `test -f 'w32-estream.c' || echo './'`w32-estream.c
libtool: compile: gcc -DHAVE_CONFIG_H -I. -I.. -DLOCALEDIR=\"/mingw/share/locale\" -I/mingw/include -g -O2 -Wall -Wpointer-arith -Wno-psabi -MT libgpg_error_la-w32-estream.lo -MD -MP -MF .deps/libgpg_error_la-w32-estream.Tpo -c w32-estream.c -DDLL_EXPORT -DPIC -o .libs/libgpg_error_la-w32-estream.o
w32-estream.c: In function '_gpgrt_w32_poll':
w32-estream.c:779:8: warning: variable 'waitinfo' set but not used [-Wunused-but-set-variable]
char waitinfo[MAXIMUM_WAIT_OBJECTS];
^~~~~~~~
w32-estream.c: In function 'func_w32_pollable_seek':
w32-estream.c:1012:23: error: 'EOPNOTSUPP' undeclared (first use in this function)
_gpg_err_set_errno (EOPNOTSUPP);
^~~~~~~~~~
w32-estream.c:1012:23: note: each undeclared identifier is reported only once for each function it appears in
w32-estream.c: In function 'func_w32_pollable_ioctl':
w32-estream.c:1038:23: error: 'EOPNOTSUPP' undeclared (first use in this function)
_gpg_err_set_errno (EOPNOTSUPP);
^~~~~~~~~~
make[3]: *** [libgpg_error_la-w32-estream.lo] Error 1
make[3]: Leaving directory `/usr/home/usr/libgpg-error-1.27/src'
make[2]: *** [all] Error 2
make[2]: Leaving directory `/usr/home/usr/libgpg-error-1.27/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/usr/home/usr/libgpg-error-1.27'
make: *** [all] Error 2

So now I have no clue what to do.