Combo changes

- move eval_material to eval-simple.c
- move phase_t to eval.h
- init.c: add eval init
- piece.h: add  piece_midval/piece_endval
- fen.c: add phase calculation
- eval-simple: fix calc_phase

src/eval.h

@@ -18,8 +18,17 @@
 
 #include "chessdefs.h"
 
+/* game phases
+ */
+enum {
+    MIDGAME,
+    ENDGAME,
+    PHASE_NB
+};
+typedef s16 phase_t;
+
 /* max pieces eval is 9*QUEEN_VALUE + 2*ROOK_VALUE + 2*BISHOP_VALUE
- * + 2*KNIGHT_VALUE which is (for a pawn valued at 100) well less than 10,000.
+ * + 2*KNIGHT_VALUE which is (for a pawn valued at 100) well less than 15,000.
  */
 #define EVAL_MAX     (SHRT_MAX)                   /* 32767 */
 #define EVAL_MIN     (-EVAL_MAX)
@@ -28,7 +37,6 @@
 
 #define EVAL_MATE    30000
 
-eval_t eval_material(pos_t *pos, bool color);
 eval_t eval_mobility(pos_t *pos, bool color);
 eval_t eval_square_control(pos_t *pos, bool color);