Improve build script

dist.sh

@@ -1,4 +1,4 @@
-#!/bin/bash -x
+#!/bin/bash
 # This script creates a mold binary distribution. The output is
 # written in this directory as `mold-$version-$arch-linux.tar.gz`
 # (e.g. `mold-1.0.3-x86_64-linux.tar.gz`).
@@ -7,8 +7,6 @@
 # libstdc++ and libcrypto but dynamically-linked to libc, libm, libz
 # and librt, as they almost always exist on any Linux systems.
 
-set -e
-
 if [ $# -ne 1 ]; then
   echo "Usage: $0 [ x86_64 | aarch64 ]"
   exit 1
@@ -23,6 +21,8 @@ fi
 version=$(grep '^VERSION =' $(dirname $0)/Makefile | sed 's/.* = //')
 dest=mold-$version-$arch-linux
 
+set -e -x
+
 docker run --platform linux/$arch -it --rm -v "$(pwd):/mold" \
   -e "OWNER=$(id -u):$(id -g)" rui314/mold-builder:latest \
   bash -c "mkdir /tmp/build &&