v8: fix v3 builds by switching to GCC 5 (mksnapshot segfaults with GCC 6)

Changed files
+2
pkgs
top-level
+2
pkgs/top-level/all-packages.nix
···
v8_3_16_14 = callPackage ../development/libraries/v8/3.16.14.nix {
inherit (python2Packages) python gyp;
cctools = darwin.cctools;
+
stdenv = overrideCC stdenv gcc5;
v8_3_24_10 = callPackage ../development/libraries/v8/3.24.10.nix {
inherit (python2Packages) python gyp;
+
stdenv = overrideCC stdenv gcc5;
v8 = callPackage ../development/libraries/v8 {