Fix shebangs and make scripts executable

INSTALL.md

@@ -130,14 +130,14 @@ cd pokeplatinum
 # 3. Building
 To set up the build system, run:
 ```
-sh config.sh
+./config.sh
 ```
 
 This is only required once. If the process is successful, you will see a new 'build' folder in the repository.
 
 To build the rom, run:
 ```
-sh build.sh
+./build.sh
 ```
 
 If everything works, then the following ROM should be built:

build.sh

@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
 
 # Set up env variable to show % of completion during ninja build
 export NINJA_STATUS="[%p %f/%t] "

clean.sh

@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
+#!/bin/sh
 
 ninja -C build clean

config.sh

@@ -1,4 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
 set -e
 
 build="build"