build: set GO15VENDOREXPERIMENT in env.sh

fjl · fjl · commit be2a264915f5 · 2016-11-16T10:54:05.000+01:00
This should fix the 'make' build with Go 1.5.
diff --git a/build/env.sh b/build/env.sh
@@ -20,7 +20,8 @@ fi
 
 # Set up the environment to use the workspace.
 GOPATH="$workspace"
-export GOPATH
+GO15VENDOREXPERIMENT=1
+export GOPATH GO15VENDOREXPERIMENT
 
 # Run the command inside the workspace.
 cd "$ethdir/go-ethereum"
