Use same path inside and outside of container to fix debugging for docker builds

build.sh

-#!/bin/sh
+#!/bin/bash
 pushd docker
 docker build -t bpftrace-builder -f Dockerfile.ubuntu .
 popd
-docker run --rm -u $(id -u):$(id -g) -v $(pwd):/bpftrace bpftrace-builder
+docker run --rm -u $(id -u):$(id -g) -v $(pwd):$(pwd) bpftrace-builder "$(pwd)"

docker/build.sh

 set -e
-cd /bpftrace
-mkdir -p build-docker
-cd build-docker
+DIR="$1/build-docker"
+mkdir -p "$DIR"
+cd "$DIR"
 cmake -DCMAKE_BUILD_TYPE=Debug ../
 make