From e174b8a8008d95730f3f73e0c2bf99a9120a4588 Mon Sep 17 00:00:00 2001
From: Mahmoud Al-Qudsi <mqudsi@neosmart.net>
Date: Wed, 25 Oct 2017 15:57:36 -0500
Subject: [PATCH] Fix build on platforms without bash

Build script build_tools/git_version_gen.sh had a hard dependency on
bash that was causing the build to fail on systems without bash.

Closes #4491
---
 build_tools/git_version_gen.sh | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/build_tools/git_version_gen.sh b/build_tools/git_version_gen.sh
index 791ac8ff7..b7faccbf4 100755
--- a/build_tools/git_version_gen.sh
+++ b/build_tools/git_version_gen.sh
@@ -1,11 +1,14 @@
-#!/bin/bash
+#!/bin/sh
 # Originally from the git sources (GIT-VERSION-GEN)
 # Presumably (C) Junio C Hamano <junkio@cox.net>
 # Reused under GPL v2.0
 # Modified for fish by David Adam <zanchey@ucc.gu.uwa.edu.au>
 
+# Obtain directory containing this script in POSIX-compatible manner
+# See https://stackoverflow.com/a/43919044/17027 (public domain)
+a="/$0"; a="${a%/*}"; a="${a:-.}"; a="${a#/}/"; BASEDIR=$(cd "$a"; pwd)
 # Find the fish git directory as two levels up from this directory.
-GIT_DIR=$(dirname $(dirname "${BASH_SOURCE[0]}"))
+GIT_DIR=$(dirname $(dirname "$a"))
 
 FBVF=FISH-BUILD-VERSION-FILE
 DEF_VER=unknown