Remove unused "m" field in LSEG.

This field has been unreferenced since 1998, and does not appear in lseg
values stored on disk (since sizeof(lseg) is only 32 bytes according to
pg_type).  There was apparently some idea of maintaining it just in values
appearing in memory, but the bookkeeping required to make that work would
surely far outweigh the cost of recalculating the line's slope when needed.
Remove it to (a) simplify matters and (b) suppress some uninitialized-field
whining from Coverity.

src/backend/utils/adt/geo_ops.c

@@ -2019,10 +2019,6 @@ lseg_in(PG_FUNCTION_ARGS)
 				(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
 				 errmsg("invalid input syntax for type lseg: \"%s\"", str)));
 
-#ifdef NOT_USED
-	lseg->m = point_sl(&lseg->p[0], &lseg->p[1]);
-#endif
-
 	PG_RETURN_LSEG_P(lseg);
 }
 
@@ -2051,10 +2047,6 @@ lseg_recv(PG_FUNCTION_ARGS)
 	lseg->p[1].x = pq_getmsgfloat8(buf);
 	lseg->p[1].y = pq_getmsgfloat8(buf);
 
-#ifdef NOT_USED
-	lseg->m = point_sl(&lseg->p[0], &lseg->p[1]);
-#endif
-
 	PG_RETURN_LSEG_P(lseg);
 }
 
@@ -2091,10 +2083,6 @@ lseg_construct(PG_FUNCTION_ARGS)
 	result->p[1].x = pt2->x;
 	result->p[1].y = pt2->y;
 
-#ifdef NOT_USED
-	result->m = point_sl(pt1, pt2);
-#endif
-
 	PG_RETURN_LSEG_P(result);
 }
 
@@ -2106,10 +2094,6 @@ statlseg_construct(LSEG *lseg, Point *pt1, Point *pt2)
 	lseg->p[0].y = pt1->y;
 	lseg->p[1].x = pt2->x;
 	lseg->p[1].y = pt2->y;
-
-#ifdef NOT_USED
-	lseg->m = point_sl(pt1, pt2);
-#endif
 }
 
 Datum
@@ -2160,9 +2144,6 @@ lseg_parallel(PG_FUNCTION_ARGS)
 	LSEG	   *l1 = PG_GETARG_LSEG_P(0);
 	LSEG	   *l2 = PG_GETARG_LSEG_P(1);
 
-#ifdef NOT_USED
-	PG_RETURN_BOOL(FPeq(l1->m, l2->m));
-#endif
 	PG_RETURN_BOOL(FPeq(point_sl(&l1->p[0], &l1->p[1]),
 						point_sl(&l2->p[0], &l2->p[1])));
 }

src/include/utils/geo_decls.h

@@ -68,8 +68,6 @@ typedef struct
 typedef struct
 {
 	Point		p[2];
-
-	double		m;				/* precomputed to save time, not in tuple */
 } LSEG;
 
 

src/test/regress/regress.c

@@ -212,7 +212,6 @@ regress_lseg_construct(LSEG *lseg, Point *pt1, Point *pt2)
 	lseg->p[0].y = pt1->y;
 	lseg->p[1].x = pt2->x;
 	lseg->p[1].y = pt2->y;
-	lseg->m = point_sl(pt1, pt2);
 }
 
 PG_FUNCTION_INFO_V1(overpaid);