[fpc-pascal] os dependency with ifdef

[Marc Santhoff]

Hi,

I' like to know how I should write code for different system. SInce I'm
no Linux user nor have any experience on MacOS I need to know how to
wrap platform dependant code.

Since I'm still fiddling with reading the serial port I have the idea
that linux and even MacOS may be very similar to my main os FreeBSD.

I do know Win32 is different, but how similar are the other os'ses?

Is there any code in the FCL or the like I can study for getting my
ifdefs right?

TIA,
Marc