Code: https://github.com/mongodb/mongo/blob/cbe2b6a6be0ae8425f7b79414434a22e1c4073e3/site_scons/mongo/generators.py#L98-L120

We use the default_variant_dir_generator function in the site_scons/mongo/generators.py file to automatically generate a directory name based on the opt & dbg settings. The way it is done right now (1) does not encompass all possible variations, (2) uses the same directory name for different variations & (3) uses hashes to generate directory names which may not be needed. A potential solution is to use the values of opt & dbg to generate a unique & descriptive directory name. For example, given the options dbg=on & opt=off, we may construct the directory name: dbg-on-opt-off.