Summary: pass decoration triple to mapfam worker routines by value (instead of by...

Summary: pass decoration triple to mapfam worker routines by value (instead of by-ref)
Keywords: fix bug 162

This changeset fixes the issues described in bug 162
(http://issues.sxemacs.org/show_bug.cgi?id=162).

The mapfam worker routine __pntw_1seq() (operate pointwise on just one sequence)
gets its decoration values (the initiator, the separator and the terminator) by
value now, i.e. on the stack.  Whereas before it got a pointer to a stack-alloc'd
struct in the main mapfam routine.

Gcc 4.8.1 probably changed the memory layout or scope rules for pointers to stack
alloc'd objects slightly, we will never know, as this hasn't been investigated.

Anyway, it's probably good to keep an eye out for similar problems that match
this pattern.