Samba 4.10.10 can't find gnutls headers on one machine

[Morgan Wesström]

Dear list,

I need some help to figure out what I broke on my system. I have two 
(almost) identical machines, one running 12.1-RELEASE and one waiting to 
be upgraded and is still on 12.0-RELEASE-p10. Configuration and software 
wise I try to keep them identical.

I recently upgraded Samba to 4.10.10 and it worked as expected on 12.1 
but the same upgrade on 12.0 fails because the configure script can't 
find the gnutls headers. Here's some command outputs from each machine:

12.1
# pkg info | grep gnutls
gnutls-3.6.10                  GNU Transport Layer Security library
# pkgconf --cflags gnutls
-I/usr/local/include -I/usr/local/include/p11-kit-1
# pkgconf --libs gnutls
-L/usr/local/lib -lgnutls

12.0
# pkg info | grep gnutls
gnutls-3.6.10                  GNU Transport Layer Security library
# pkgconf --cflags gnutls
-I/usr/local/include -I/usr/local/include/p11-kit-1
# pkgconf --libs gnutls
-L/usr/local/lib -lgnutls

Everything seems identical to me. Files are installed in 
/usr/local/include/gnutls. Unfortunately I'm too stupid to figure out 
how the Samba configure script works. It seems to be made in Python and 
I can't figure out how it checks for gnutls.

python27-2.7.17 and python36-3.6.9 are installed on both machines.

Any suggestions to help me figure out what I have broken would be 
appreciated.

Regards
Morgan Wesström