Replace build.sh with make to manage airtime_mvc

tools/version.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+set -u
+
+error() {
+  echo >&2 "error: $*"
+  exit 1
+}
+
+command -v git > /dev/null || error "git command not found!"
+command -v tee > /dev/null || error "tee command not found!"
+
+typeset -r version_file="VERSION"
+
+if [[ "$(git rev-parse --is-inside-work-tree 2> /dev/null)" == "true" ]]; then
+  tag=$(git tag --points-at HEAD | tee "$version_file" || error "could not extract tag")
+  if [[ -z "$tag" ]]; then
+    git rev-parse --short HEAD > "$version_file" || error "could not extract commit sha"
+  fi
+else
+  if [[ ! -f "$version_file" ]]; then
+    echo "could not detect version" > VERSION
+  fi
+fi