If we give the compiler any quoted file path with spaces, they are interpreted as separate arguments, despite the quotes. Here are a couple examples.

Path to Jakt runtime contains spaces:

>jakt src\main.jakt -I "E:\Path To Jakt\runtime" -o output_file     
clang++: error: no such file or directory: 'To'
clang++: error: no such file or directory: 'Jakt\runtime'

Path to write binary file to contains spaces:

>jakt src\main.jakt -I E:\jakt\runtime -o "output dir\output_file"
clang++: error: no such file or directory: 'dir\output_file'
clang++: error: no such file or directory: 'build/output'
clang++: error: no such file or directory: 'dir\output_file.cpp'
clang++: error: no input files

I am running Windows 10.