Merge line-drawing changes into pre-release trunk

diff --cc bedstead.c
index b3dd6aed7b4fcb6add7671d200fb1cfcd3365cc8,5d793bd6fffd27e4f972aa74b3af15162a3d5d38..0ed84162b5ffadf3a0ef7374ea8f5ac7a9c4ce49
--- 1/bedstead.c
--- 2/bedstead.c
+++ b/bedstead.c
@@@ -218,9 -210,10 +218,12 @@@ static struct glyph 
  #define MOS4 0x04 /* 4-cell mosaic graphics character */
  #define SEP6 (SEP | MOS6)
  #define SEP4 (SEP | MOS4)
--#define IS_ALIAS 0x08
- #define IS_SUBR  0x10
 -#define JOIN_L 0x10 /* Copy left column leftwards to join to adjacent character. */
 -#define JOIN_U 0x20 /* Copy top row upwards ditto. */
++#define JOIN_L 0x08 /* Copy left column leftward to join to next character. */
++#define JOIN_U 0x10 /* Copy top row upwards ditto. */
+ #define JOIN (JOIN_L | JOIN_U)
++#define IS_ALIAS 0x20
++#define IS_SUBR  0x40
 +      uint_least16_t left_sidebearing; /* Set when outline generated. */
  } glyphs[] = {
   /*
    * The first batch of glyphs comes from the code tables at the end of