Add newline between compile commands of the generated code

[e-kayrakli]

This PR adds newline between the compilation commands of the generated code.

Context: CHAMPS team tried to use --incremental to reduce the backend's memory
footprint. But they got errors from exec command because we were simply
running a huge one-liner to compile the generated code. Note that the
compilation of individual files were still separated, but only with ;. So it
was still a single huge argument for execvp.

I am not fond of the solution but we couldn't think of any other quick alternative.

Test

• linux64 --incremental in examples
• linux64 --no-local --incremental in examples
• linux64

[e-kayrakli]

I confirmed that this branch enables CHAMPS to compile with --incremental. I'll run some paratests.