diff --git a/include/config.h b/include/config.h
index 2da69acd..05740b1b 100644
--- a/include/config.h
+++ b/include/config.h
@@ -52,7 +52,7 @@
 //#define PVS_AI
 #define MTDF_AI
 
-#ifdef WIN32
+#ifdef _MSC_VER
 #define PERFECT_AI_SUPPORT
 #endif
 
diff --git a/src/test/test.cpp b/src/test/test.cpp
index 3a227012..0846a2e2 100644
--- a/src/test/test.cpp
+++ b/src/test/test.cpp
@@ -31,7 +31,9 @@
 #include "option.h"
 #include "test.h"
 
+#ifdef PERFECT_AI_SUPPORT
 #include "perfect/perfect.h"
+#endif
 
 #ifdef TEST_MODE
 #ifdef QT_GUI_LIB
@@ -220,9 +222,11 @@ void Test::readFromMemory()
             sharedMemory.unlock();
             readStr = str;
 
+#ifdef PERFECT_AI_SUPPORT
             if (gameOptions.getPerfectAiEnabled()) {
                 perfect_command(str.toStdString().c_str());
             }
+#endif
 
             emit command(str.toStdString());
         }
diff --git a/src/ui/qt/game.cpp b/src/ui/qt/game.cpp
index 930b7636..19b1b05c 100644
--- a/src/ui/qt/game.cpp
+++ b/src/ui/qt/game.cpp
@@ -40,7 +40,9 @@
 #include "client.h"
 #include "option.h"
 
+#ifdef PERFECT_AI_SUPPORT
 #include "perfect/perfect.h"
+#endif
 
 using namespace std;
 
@@ -230,9 +232,11 @@ void Game::gameReset()
         moveHistory.emplace_back(bak);
     }    
 
+#ifdef PERFECT_AI_SUPPORT
     if (gameOptions.getPerfectAiEnabled()) {
         perfect_reset();
     }
+#endif
 
     position.reset();
     elapsedSeconds[BLACK] = elapsedSeconds[WHITE] = 0;
@@ -596,11 +600,13 @@ void Game::setPerfectAi(bool enabled)
     gameOptions.setPerfectAiEnabled(enabled);
     settings->setValue("Options/PerfectAI", enabled);
 
+#ifdef PERFECT_AI_SUPPORT
     if (enabled) {
         perfect_reset();
     } else {
         perfect_exit();
     }
+#endif
 }
 
 void Game::setIDS(bool enabled)
@@ -918,9 +924,11 @@ bool Game::actionPiece(QPointF p)
     }
 
     if (result) {
+#ifdef PERFECT_AI_SUPPORT
         if (gameOptions.getPerfectAiEnabled()) {
             perfect_command((char *)position.record);
         }
+#endif
 
         moveHistory.emplace_back(position.record);