🚀 go-pugleaf

gdb4.7 target==sparc, host==sparc (g++ from gcc2.2.2) does
a sign extension when it extracts enumerations contained in bit fields;
gdb4.6 does not do the sign extension, and neither does gcc from gcc2.2.2.
(Note that enums contained in bitfields are legal in c++, since they
are integral types)

For the program at the bottom,
breaking at the first printf in main,
and doing
  (gdb4.7) print e
  $1 = {
    x = -2
  }
  (gdb4.7) print u
  $2 = {
    x = 2
  }
whereas in gdb4.6 doing the same thing:
  (gdb4.6) print e
  $1 = {
    x = VAL2
  }
  (gdb4.6) print u
  $2 = {
    x = 2
  }
is better, and agrees in the sign-extendedness behaviour
with the output of executing the program:
  VAL2 = 2
  e.x = 2
  u.x = 2