All the dev-lang/go ebuilds are not correctly setup to handle the transition to gcc-6 when built with USE=gccgo, because gcc-6 produces a "go-6" binary, but these ebuilds are hard-coded to only attempt "go-5".
DEPEND is defined as:
gccgo? ( >=sys-devel/gcc-5[go] )
which matches gcc-6
However, src_compile() is hard-coded to execute:
local go_binary=$(gcc-config --get-bin-path)/go-5
This causes the ebuild to fail with:
go-5: command not found
On my system, I converted all 3 instances of:
and everything worked perfectly. Not sure if this is the correct long-term solution.
I added your fix to go-1.8 since that seems to be the best solution at
Thanks for the report.