Hi,

I tried to re-build with the closest build-type I could find in
config.guess "x86_64" and used "-D__ia64__" in CFLAGS, but ran into:

/usr/bin/c89 -g -Wnowarn -D__ia64__ -D_TANDEM_SOURCE
-D_XOPEN_SOURCE_EXTENDED=1
-D_SIGMAX=44 -Woptimize=0   -I. -I.  -c eval.c
        top = (VALUE*)ctx.uc_mcontext.sc_ar_bsp;
                                      ^
"/home/ruby/eval.c", line 9998: error(1565): struct "mcontext" has no
          field "sc_ar_bsp"


This is because my local version of ucontext.h contains:

....
typedef int     greg_t;
typedef greg_t  gregset_t[38];

typedef struct  mcontext
{
        gregset_t       gpregs;
} mcontext_t;

typedef struct  ucontext
{
        mcontext_t      uc_mcontext;
} ucontext_t;
....

I don't have Boehm's GC or Guile Scheme interpreter on my machine, so
now I'm stuck.