geo_ops.c is broken

The recently checked-in backend/utils/adt/geo_ops.c does not compile
under gcc 2.7.2.2, because it has

#define LINEDEBUG

followed by several instances of

#if LINEDEBUG

... in other words #if with an empty expression, which I think gcc
has every right to object to. Either the #if's ought to be #ifdef's
or LINEDEBUG has to be #define'd as 1 rather than empty.

I changed the #if's to #ifdef's and found that it *still* doesn't
compile, because the code within the if's is seriously broken ---
it's got lines like
result->C = pt1->x;
where result is a char * and pt1 isn't even declared.

Backing out the #define LINEDEBUG makes it compile, but who checked
this stuff in anyway?

grumble, tom lane