Ensure that all compile*.sh scripts use the CC env var

These commits fixes issues where the user would have to edit the simple compilation scripts in order to build with their desired compiler.
Now, certain issues may still be present, which is why this pull request should be checked and tested first.
For the most part though, it should really just work by running the script, and using a different compiler can easily be specified through the use of the CC environment variable.

For instance, to compile using clang:

    CC=clang ./compile.sh