[patch] Compile fix for 64-bit HPUX

[Randolph Chung]

> The autoconf manual says:
> 
> `${VAR:-VALUE}'
>      Old BSD shells, including the Ultrix `sh', don't accept the colon
>      for any shell substitution, and complain and die.
> 
> Thus in fact, omitting the colon is more portable.

Thanks for all the good in depth explanation; I have to confess that I
just copied that construct from another part of the autoconf script :-P

randolph