control interface not starting

[ck+hostap at bl4ckb0x.de]

Hi!
I've installed Gentoo on my Raspberry Pi 3 and trying to use the buildin 
WiFi (Broadcom 43430).

net-wireless/wpa_supplicant-2.5-r1::gentoo  USE="readline ssl wps -ap 
-dbus -eap-sim -fasteap -gnutls -hs2-0 (-libressl) -p2p (-ps3) -qt4 -qt5 
(-selinux) -smartcard -tdls -uncommon-eap-types (-wimax)" 0 KiB

I am able to start, when I do comment out my ctrl_interface.

When I do add it, ist fails.

Using existing control interface directory.
ctrl_interface_group=10 (from group name 'wheel')
ctrl_iface bind(PF_UNIX) failed: Invalid argument
ctrl_iface exists, but does not allow connections - assuming it was 
leftover from forced program termination
Could not unlink existing ctrl_iface socket 
'/var/run/wpa_supplicant/wlan0': No such file or directory
Failed to initialize control interface 'DIR=/var/run/wpa_supplicant 
GROUP=wheel'.
You may have another wpa_supplicant process already running or the file 
was
left by an unclean termination of wpa_supplicant in which case you will 
need
to manually remove this file before starting wpa_supplicant again.

Failed to add interface wlan0
My guess, it has something with ctrl_iface bind(PF_UNIX) failed: Invalid 
argument to do.
But I've no clue, what could be causing this.
/var/run/wpa_supplicant/wlan0' does NOT exist.

/etc/wpa_supplicant/wpa_supplicant.conf:
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=wheel
update_config=1
network={ }
[..]

Any ideas?

Thanks!
Conrad