trezor-crypto | lock Do n't use this repo , use the new monorepo | Cryptography library

Let's say I want to use mnemonic_generate function from https://github.com/trezor/trezor-crypto/blob/master/bip39.c in my code (actually I want to use many others from the repository but let's just consider this). I have cloned the repo on my system. I can do make and it works. But I have a separate .c file in which I have #include"relative/path/to/bip39.c" And I try to call mnemonic_generate but it throws a lot of errors of the type undefined reference to 'X' (for example undefined reference to random_buffer and so on). I understand that this file in turn is trying to include other files which might contain the definitions of these undefined things but they are not getting included for some reason. Why is this happening and how to fix this?

The main reason I was confused was because I didn't know (Well I had studied but wasn't conscious of) the difference between compiling and linking. I also didn't know what a Makefile is and why do we need one. This is how I ended up solving it