Remove all warnings 

```
shellcheck -x bin/build bin/compile bin/detect bin/release bin/support/bash_functions.sh
⛄ 2.7.2 🚀  ~/Documents/projects/work/minimal-ruby (schneems/shellcheck)
$ echo $?
0
```

The java buildpack exports this file:

```
export JAVA_HOME=/tmp/build_c6a36294/.jdk
export PATH=$JAVA_HOME/bin:$PATH
export LD_LIBRARY_PATH="$JAVA_HOME/jre/lib/amd64/server:$LD_LIBRARY_PATH"
```

Which raises this error when sourcing with strict mode on:

```
line 3: LD_LIBRARY_PATH: unbound variable
```

The solution from http://redsymbol.net/articles/unofficial-bash-strict-mode/#sourcing-nonconforming-document and @edmorley is to reduce the checking level before sourcing and then to increase it after.

CircleCI-Public/shellcheck-orb#33 (comment)