Since dev c++ seems to use GCC, the first thing I'd try is to compile using the make.bat script. There's a new block in it where you can adjust path/filenames of the GCC executables:
Originally Posted by email@example.com
After that, calling "make" compiles a 32-bit version using GCC32/GPP32, calling "make 64" compiles a 64-bit version using GCC64/GPP64.
REM gcc/g++ 32-bit/64-bit commands - change them according to your environment
Once this works, you secured that compiling without the IDE works (it should, as dev c++ uses MinGw GCC/G++ 4.8.1 which was used to compile older Precomp releases). The next thing I'd try is to put every source file (.cpp/.c/.h) from the root directory and the contrib directories into a project - keep the directory structure, if possible - and try to compile it using the IDE. It can be a long way to achieve this, but it gives you breakpoints and debugging, so if you want to do something with the code, it's worth the pain