Problem with PortGroup github

[Gustaf Neumann]

Dear all,

I am experiencing troubles with changing a portfile to use the github 
PortGroup.
When "port" tries to fetch from github via the portgroup, the fetch 
fails with
"SSL peer handshake failed, the server most likely requires a client 
certificate to connect".
Interestingly, the problem disappears, when "--ignore-ssl-cert" is removed
(see script below).

Is there a bug in the github portgroup or with the github instance, i am
connecting to, or  maybe something wrong on my installation?

This is with MacOS X 10.10.5, i have 1073 ports installed, never
experienced a problem with macports+github before.

-g
PS: Ticket is at: https://trac.macports.org/ticket/49359

#################################################################
#!/opt/local/libexec/macports/bin/tclsh8.5

package require fetch_common 1.0

set source https://github.com/downloads/tDOM/tdom/tdom-0.8.3.tgz
set target /opt/local/var/macports/distfiles/tDOM/tdom-0.8.3.tgz.TMP

puts stderr "Fetch in the style of the github PortGroup:"
if {[catch {curl fetch --ignore-ssl-cert --progress builtin $source $target} errorMsg]} {
     puts stderr "fetch failed: $errorMsg"
}
puts stderr "\nFetch in old-style:"
if {[catch {curl fetch --progress builtin $source $target} errorMsg]} {
     puts stderr "fetch failed: $errorMsg"
}