GCC pre-compile directive indicating Linux or BSD
 

Is there a pre-compile directive in GCC that will indicate whether it is compiling on a Linux system or BSD (or other) OS?

I think i've answered my own question.

FYI, I think what you're talking about is called a preprocessor directive, not "pre-compile". From the title, I thought at first that you were asking about precompiled headers.

My lexicon stands corrected