diff --git a/build/builder.sh b/build/builder.sh
index 1a6430037793..330b8dd90a86 100755
--- a/build/builder.sh
+++ b/build/builder.sh
@@ -66,21 +66,22 @@ cockroach_toplevel="$(dirname $(cd $(dirname $0); pwd))"
 # This script supports both circleci and development hosts, so it must
 # support cases where the architecture inside the container is
 # different from that outside the container. We map /src/ directly
-# into the container because it is architecture-independent, and /pkg/
-# because every subdirectory is tagged with its architecture. We also
-# map certain subdirectories of ${GOPATH}/pkg into ${GOROOT}/pkg so
-# they can be used to cache builds of the standard library. /bin/ is
-# mapped separately to avoid clobbering the host's binaries. Note that
-# the path used for the /bin/ mapping is also used in the defaultBinary
+# into the container because it is architecture-independent. We then
+# map certain subdirectories of ${GOPATH}/pkg into both ${GOPATH}/pkg
+# and ${GOROOT}/pkg. The ${GOROOT} mapping is needed so they can be
+# used to cache builds of the standard library. /bin/ is mapped
+# separately to avoid clobbering the host's binaries. Note that the
+# path used for the /bin/ mapping is also used in the defaultBinary
 # function of localcluster.go.
 #
 # -i causes some commands (including `git diff`) to attempt to use
 # a pager, so we override $PAGER to disable.
 docker run -i ${tty-} ${rm} \
   --volume="${gopath0}/src:/go/src" \
-  --volume="${gopath0}/pkg:/go/pkg" \
-  --volume="${gopath0}/pkg/docker_amd64:/usr/src/go/pkg/linux_amd64" \
-  --volume="${gopath0}/pkg/docker_amd64_race:/usr/src/go/pkg/linux_amd64_race" \
+  --volume="${gopath0}/pkg/docker_amd64:/go/pkg/linux_amd64" \
+  --volume="${gopath0}/pkg/docker_amd64_race:/go/pkg/linux_amd64_race" \
+  --volume="${gopath0}/pkg/docker_amd64:/usr/local/go/pkg/linux_amd64" \
+  --volume="${gopath0}/pkg/docker_amd64_race:/usr/local/go/pkg/linux_amd64_race" \
   --volume="${gopath0}/bin/docker_amd64:/go/bin" \
   --volume="${HOME}/.jspm:/root/.jspm" \
   --volume="${HOME}/.npm:/root/.npm" \