Suricata

This issue appears to affect compiling Suricata 4.1.0 from source. I noticed that when attempting to compile from source with rustc and cargo installed to get all of the neat new features, that compiling suricata would fail due to CARGO_TARGET_DIR not be able to handle spaces in directory paths. I know that having spaces in your path is a sin against nature, but this wasn't a problem that I ever noticed before.

Operating Systems: Ubuntu 16.04.5 and 18.04.1

Problem: compiling Suricata 4.1.0 with rust support fails when there are spaces in the CARGO_TARGET_DIR (see attached image)
Expected Result: Should be able to handle spaces in path, barring this expected result if not possible, then documentation stating that this is a limitation to be aware when compiling from source.
Work-Around: Don't have spaces in path.