In kernel land header files from <sys/> domain oftenly implicitly expect that 
a set of other header files has been included. For example, <sys/conf.h> 
expects that <sys/param.h> has been included and so on. When i'm writting a 
kernel code from scratch, for example a character device driver, i'd to 
remember which files and in what order to include. Right now for IO_NDELAY 
i'd to include <sys/vnode.h> but looks like it expects some other files to be 
here so i'd to spent time to traverse headers/code examples to find out a 
right combination. IMHO it's at least a bit annoying :(

On the other hand i don't have such problems due to obvious reasons. So my 
question is: is there someone work going on on making kernel includes to be a 
bit more user/developer friendly as userland are? When i can just #include 
<sys/vnode.h> in a naked C file and compile it without warnings or errors. 
AFAIU there aren't *too* much of work to unify kernel include files (though i 
can be wrong of course).

// wbr