This makes it possible to build and test mold in a path that contains
whitespace characters - with the notable exception of the tests where
`LD_PRELOAD` is used. That's because `LD_PRELOAD` unconditionally treats
any whitespace as separator, regardless of quoting.
The following ShellCheck warnings are eliminated by this commit:
* SC2046: Quote this to prevent word splitting.
* SC2086: Double quote to prevent globbing and word splitting.
Signed-off-by: Christoph Erhardt <github@sicherha.de>
