--- configure.orig	2017-04-10 09:22:14 UTC
+++ configure
@@ -1,9 +1,10 @@
-#!/usr/bin/env bash
+#!/bin/sh
 
 PREFIX=/usr
 
 if [ ! -z "$1" ]; then
-  if [[ "$1" =~ ^--prefix= ]]; then
+  ARGNAME=$(echo $1 | cut -d= -f1)
+  if [ "x${ARGNAME}" = "x--prefix" ]; then
     PREFIX=$(echo $1 | cut -d= -f2)
   else
     echo "Usage: $0 [--prefix=<path>]"