Comments on pmake diffs for building on Linux

[M. Warner Losh]

In message: <20080304153651.I41184 at fledge.watson.org>
            Robert Watson <rwatson at FreeBSD.org> writes:
: On Tue, 4 Mar 2008, M. Warner Losh wrote:
: 
: > : In most ports of FreeBSD parts to Linux that I've seen, the preferred solution
: > : has to been to bring the entire FreeBSD queue.h with you rather than relying
: > : on the native Linux queue.h.  This is what we do for OpenBSM, for example;
: > : this also helps out when you get to Mac OS X, Solaris, etc, where all the
: > : queue.h's continue to vary in subtle ways.  This depends a fair amount on a
: > : lack of header pollution in the OS's own include files, of course...
: >
: > I was rather hoping for something that could be used without any of that 
: > nonsense...
: 
: Sadly, nonsense seems to be the name of the game in software portability. 
: Here's the broken autoconf garbage I use to pick out adequate queue.h's from 
: inadequate ones:
: 
: # sys/queue.h exists on most systems, but its capabilities vary a great deal.
: # test for LIST_FIRST and TAILQ_FOREACH_SAFE, which appears to not exist in
: # all of them, and are necessary for OpenBSM.
: AC_TRY_LINK([
:          #include <sys/queue.h>
: ], [
: 
:          #ifndef LIST_FIRST
:          #error LIST_FIRST missing
:          #endif
:          #ifndef TAILQ_FOREACH_SAFE
:          #error TAILQ_FOREACH_SAFE
:          #endif
: ], [
: AC_DEFINE(HAVE_FULL_QUEUE_H,, Define if queue.h includes LIST_FIRST)
: ])
: 
: Note that there are at least a couple of mostly stylistic bugs there (could 
: use compile rather than link, definition description is poor, errors are 
: inconsistent). :-)  I found that on both Linux and Mac OS X, the queue.h's 
: didn't have everything I wanted.

Right.  But I'm not going to use autoconf.  It is totally off the
table as far as I'm concerned.

Warner