Remove duplication. (#2068)

always use the implementation of gives_check in position, no need to
hand-inline part of the implementation in search.

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 57895 W: 12632 L: 12582 D: 32681
http://tests.stockfishchess.org/tests/view/5c9eaa4b0ebc5925cfffc9e3

No functional change.

src/search.cpp

@@ -116,13 +116,6 @@ namespace {
   void update_quiet_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietCount, int bonus);
   void update_capture_stats(const Position& pos, Move move, Move* captures, int captureCount, int bonus);
 
-  inline bool gives_check(const Position& pos, Move move) {
-    Color us = pos.side_to_move();
-    return  type_of(move) == NORMAL && !(pos.blockers_for_king(~us) & pos.pieces(us))
-          ? pos.check_squares(type_of(pos.moved_piece(move))) & to_sq(move)
-          : pos.gives_check(move);
-  }
-
   // perft() is our utility to verify move generation. All the leaf nodes up
   // to the given depth are generated and counted, and the sum is returned.
   template<bool Root>
@@ -887,7 +880,7 @@ namespace {
       extension = DEPTH_ZERO;
       captureOrPromotion = pos.capture_or_promotion(move);
       movedPiece = pos.moved_piece(move);
-      givesCheck = gives_check(pos, move);
+      givesCheck = pos.gives_check(move);
 
       // Step 13. Extensions (~70 Elo)
 
@@ -1313,7 +1306,7 @@ namespace {
     {
       assert(is_ok(move));
 
-      givesCheck = gives_check(pos, move);
+      givesCheck = pos.gives_check(move);
 
       moveCount++;