Update compile.sh to make use of CC environment variable.
Fix using && as opposed to the correct ||.
Use new CC environment variable COMPILER system in all compile*.sh files.
Deprecate COMPILER variable.
Improve shell compability by conforming to POSIX (more).
Merge pull request #21 from necrophcodr/develop

Ensure that all compile*.sh scripts use the CC env var (enhances pull request #19)