unable to find gnutls in configure script run

[Van Ly <van.ly%sdf.org@localhost>]

Hello,

I was able to build emacs-29.4, building pretest emacs-30.0.91 fails at
the diagnostic in the configure script run as follows

  1 configure: error: The following required libraries were not found:
  2      gnutls
  3 Maybe some development libraries/packages are missing?
  4 To build anyway, give:
  5      --with-gnutls=ifavailable
  6 as options to configure

To work around this problem PKG_CONFIG_PATH needs to be set as
follows in the call to configure

   $ env PKG_CONFIG_PATH=/usr/pkg/lib/pkgconfig ../30.0.91/configure

Where is the right place to set PKG_CONFIG_PATH ? /etc/mk.conf ?

When I built emacs-29.4 I probably had an earlier pkgsrc release and
didn't have this problem because PKG_CONFIG_PATH was set right
somewhere. I have tried building packages from pkgsrc and pkgsrc/wip and
abandoned runs before completion, I don't know if this may have left
environment variables in inconsistent state.

Thanks in advance.

-- 
vl