I'm looking for something to abstract the standard operating system functionality in C/C++: span/kill a thread, send/receive a message, start/stop a timer, maybe even memory management, although I can probably handle that myself with my own buffer pool.

I want to to be able to develop and unit test on Linux/windows and then recompile the c/c++ code for various target O/Ses (for embedded systems: eCos, FreeRTOS, VxWorks, etc)

Something as "light" as possible would be best, hopefully just a library, maybe even a collection of macros.