Add FreeBSD cert bundle

* doc/misc/emacs-gnutls.texi (Help For Users): Document
FreeBSD bundle.

* lisp/net/gnutls.el (gnutls-trustfiles): Add FreeBSD cert bundle.

Backport:

(cherry picked from commit 60c0f1a1)

doc/misc/emacs-gnutls.texi

@@ -123,14 +123,15 @@ The @code{gnutls-trustfiles} variable is a list of trustfiles
 host name (although @code{gnutls-negotiate} supports a trustfile per
 connection so it could be done if needed).  The trustfiles can be in
 PEM or DER format and examples can be found in most Unix
-distributions.  By default four locations are tried in this order:
-@file{/etc/ssl/certs/ca-certificates.crt} for Debian, Ubuntu, Gentoo
-and Arch Linux; @file{/etc/pki/tls/certs/ca-bundle.crt} for Fedora
-and RHEL; @file{/etc/ssl/ca-bundle.pem} for Suse;
-@file{/usr/ssl/certs/ca-bundle.crt} for Cygwin.  You can easily
-customize @code{gnutls-trustfiles} to be something else, but let us
-know if you do, so we can make the change to benefit the other users
-of that platform.
+distributions.  By default the following locations are tried in this
+order: @file{/etc/ssl/certs/ca-certificates.crt} for Debian, Ubuntu,
+Gentoo and Arch Linux; @file{/etc/pki/tls/certs/ca-bundle.crt} for
+Fedora and RHEL; @file{/etc/ssl/ca-bundle.pem} for Suse;
+@file{/usr/ssl/certs/ca-bundle.crt} for Cygwin;
+@file{/usr/local/share/certs/ca-root-nss.crt} for FreeBSD.  You can
+easily customize @code{gnutls-trustfiles} to be something else, but
+let us know if you do, so we can make the change to benefit the other
+users of that platform.
 @end defvar
 
 @defvar gnutls-verify-error

lisp/net/gnutls.el

@@ -67,10 +67,11 @@ set this variable to \"normal:-dhe-rsa\"."
 
 (defcustom gnutls-trustfiles
   '(
-    "/etc/ssl/certs/ca-certificates.crt" ; Debian, Ubuntu, Gentoo and Arch Linux
-    "/etc/pki/tls/certs/ca-bundle.crt"   ; Fedora and RHEL
-    "/etc/ssl/ca-bundle.pem"             ; Suse
-    "/usr/ssl/certs/ca-bundle.crt"       ; Cygwin
+    "/etc/ssl/certs/ca-certificates.crt"     ; Debian, Ubuntu, Gentoo and Arch Linux
+    "/etc/pki/tls/certs/ca-bundle.crt"       ; Fedora and RHEL
+    "/etc/ssl/ca-bundle.pem"                 ; Suse
+    "/usr/ssl/certs/ca-bundle.crt"           ; Cygwin
+    "/usr/local/share/certs/ca-root-nss.crt" ; FreeBSD
     )
   "List of CA bundle location filenames or a function returning said list.
 The files may be in PEM or DER format, as per the GnuTLS documentation.