except for a linker error: it does not find references to the routines scrypto_core, sha256_use4way and the other ones defined in the assembly files scrypt-x64.S, scrypt-x86.S, etc.
I'm guessing a little bit here as I don't have DevCPP, but this sounds like it is probably because the two different compilers (as and DevCpp) don't mangle the names in a similar format. So inlining the assembly within a DevCpp compiled file will probably work just fine to resolve this. If not, you might be able to use compile-time flags to tell DevCpp to generate object files compatible with standard 'as' output?