Build: get rid of UseIt.sh

The build system uses relative paths to the toolchain binaries, so
modifying $PATH is no longer necessary, and nothing needs
$SERENITY_ROOT anymore.

Toolchain/BuildIt.sh

@@ -16,7 +16,6 @@ echo PREFIX is "$PREFIX"
 echo SYSROOT is "$SYSROOT"
 
 mkdir -p "$DIR/Tarballs"
-source "$DIR/UseIt.sh"
 
 BINUTILS_VERSION="2.33.1"
 BINUTILS_MD5SUM="1a6b16bcc926e312633fcc3fae14ba0a"

Toolchain/UseIt.sh

@@ -1,9 +0,0 @@
-#!/bin/bash
-
-# This file will need to be run in bash, for now.
-
-DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
-export PATH="$DIR/Local/bin:$PATH"
-export TOOLCHAIN="$DIR"
-export SERENITY_ROOT="$DIR/.."
-echo "$PATH"