364.12 - libGL error: unable to load driver: swrast_dri.so

Just merged properly latest beta from gentoo portage to my Sabayon GNOME 16.04 x86_64 multilib distro and got steam error with ligGL, previous libglvnd driver was working fine despite I am having to do such launch command for dota 2 “__GLVND_DISALLOW_PATCHING=1 %command%” to launch the game. But now its more frustrating to me and even steam wont launch @_@ Please help! How I can work around these problem and continue to use 364.12 driver?

/home/sergey/.local/share/Steam/steam.sh: line 159: DISTRIB_RELEASE: unbound variable
/home/sergey/.local/share/Steam/steam.sh: line 159: DISTRIB_RELEASE: unbound variable
Running Steam on sabayon  64-bit
/home/sergey/.local/share/Steam/steam.sh: line 159: DISTRIB_RELEASE: unbound variable
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(1457636973)
libGL error: unable to load driver: swrast_dri.so
libGL error: failed to load driver: swrast

Just updated steam and these problem is gone. Strangely it solved by itself.

maybe the problem is libstdc++ and solution are these:
https://bbs.archlinux.org/viewtopic.php?id=193802
https://wiki.archlinux.org/index.php/Steam#Using_native_runtime