sqlite uses something like this approach too, and there are additional optimisation advantages from keeping everything in a single file:

https://sqlite.org/amalgamation.html

    Over 100 separate source files are concatenated into a single large file of C-code named "sqlite3.c" and referred to as "the amalgamation". The amalgamation contains everything an application needs to embed SQLite.
    
    Combining all the code for SQLite into one big file makes SQLite easier to deploy — there is just one file to keep track of. And because all code is in a single translation unit, compilers can do better inter-procedure and inlining optimization resulting in machine code that is between 5% and 10% faster.