As an HPC cross platform developer, I have spent a good part of my 20s working on scientific codes under different operating systems. Windows, Mac, LINUX, HPUX, AIX, IRIX, Solaris. Building /compiling code is a full time job, not to mention porting and making changes due to the API differences. This is what I call the #ifdef jungle.
In any case, I found a group of 3 musketeers, that shared my pain, and we would like to save you time when it comes to porting your applications to Windows, where almost a billion users can run YOUR code. The wonderful folks at Interopsystems agreed to host our project for us on their website. http://www.interopcommunity.com/dictionary/index.php
This dictionary is organized by frequently used HPC Unix calls. Each entry show the Unix function, its Windows equivalent (if it exists), required header files, an example of use, and related discussion. As you (or your compiler) discovers functions that are platform-specific or otherwise need modification, you can look up the offending function to find out what changes should be done. Information not specific to a function as well as overall suggestions and strategies can be found in the Porting Tips.
We hope this will save you time, but also please provide us with feedbacks on the site. Feel free to discuss and provide your personal porting tips, and we would love to add them to the collection.