Fix sha1 on premake linux

premake5.lua

@@ -331,7 +331,7 @@ project "re3"
 		prebuildcommands { '"%{prj.location}..\\printHash.bat" "%{prj.location}..\\src\\extras\\GitSHA1.cpp"' }
 
 	filter "platforms:not win*"
-		prebuildcommands { '"%{prj.location}../printHash.sh" "%{prj.location}../src/extras/GitSHA1.cpp"' }
+		prebuildcommands { '"%{prj.location}/../printHash.sh" "%{prj.location}/../src/extras/GitSHA1.cpp"' }
 
 	filter "platforms:win*glfw*"
 		staticruntime "off"

printHash.sh

@@ -1,12 +1,10 @@
-#!/usr/bin/bash
+#!/bin/bash
 
 > $1
 
 echo -n "#define GIT_SHA1 \"" > $1
 
-git --version 2>&1 >/dev/null
-GIT_IS_AVAILABLE=$?
-if [ $GIT_IS_AVAILABLE -ne 0 ]; then
+if (command -v "git" >/dev/null) then
 git rev-parse --short HEAD | tr -d '\n' >> $1
 fi