built with SCM_DEBUG=1 lately?

[Ken Raeburn]

I was running into some problems with free() reporting unaligned 
pointers on my mac laptop, and decided to try switching on more 
debugging options.  I tried building with SCM_DEBUG=1, and several 
files needed tweaking.  Mostly in minor ways, due to -Werror -- %d for 
long values, stuff like that.  I'll send out a patch soon.

But after I got guile building again, it died with this error in the 
snarf step (first message is my added instrumentation).

../../source/libguile/throw.c:626: non-pair accessed with SCM_CDR: 
x=312960 x->car=50d7f
Non-pair accessed with SCM_C[AD]R: `#<winder 312960>?

  for (wind_goal = scm_i_dynwinds ();
       !scm_is_eq (SCM_CDAR (wind_goal), jmpbuf);    <<<----
       wind_goal = SCM_CDR (wind_goal))
    ;

So it's got a cons cell, but the car of the cons cell is not a plain 
cons cell but a "winder" smob object.  Perhaps the equivalent of 
WINDER_PROC or WINDER_DATA is what's desired here?

Ken