make.conf options and poudriere

[Victor Sudakov]

Dear Colleagues,

I'm trying to set per-port specific options as written in
https://forums.freebsd.org/threads/52871/

For example, I have tried:
"net-mgmt_flow-tools_UNSET= GCC"
and 
"net-mgmt_flow-tools_UNSET= USE_GCC"

but the port still requires lang/gcc. However, if I comment out
"USE_GCC" directly in the net-mgmt/flow-tools/Makefile, it works for me.

What am I doing wrong? I would like to be able to set/unset this
variable for different sets in poudriere, without editing the ports's
Makefile itself.

-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
AS43859