Fixed compiler warnings.

The winsock2.h header should be always included before windows.h header (or we should define WIN32_LEAN_AND_MEAN). It's because windows.h header includes also winsock.h header and there is possible conflict between winsock and winsock2.

I didn't test in on Visual Studio yet. I hope there is no WIN32_LEAN_AND_MEAN redefinition errors...

src/graphics/gl_headers.hpp

@@ -41,7 +41,7 @@ extern "C" {
 #elif defined(ANDROID)
 #    include <GLES/gl.h>
 #elif defined(WIN32)
-#    define _WINSOCKAPI_
+#    define WIN32_LEAN_AND_MEAN
 #    include <windows.h>
 #else
 #define GL_GLEXT_PROTOTYPES

src/graphics/irr_driver.cpp

@@ -82,6 +82,7 @@ please use the included version."
 using namespace irr;
 
 #ifdef WIN32
+#define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #endif
 #if defined(__linux__) && !defined(ANDROID)

src/io/file_manager.cpp

@@ -52,6 +52,7 @@ namespace irr {
 #  include <dirent.h>
 #  include <unistd.h>
 #else
+#  define WIN32_LEAN_AND_MEAN
 #  include <direct.h>
 #  include <windows.h>
 #  include <stdio.h>

src/main.cpp

@@ -122,8 +122,6 @@
 #    include <unistd.h>
 #  endif
 #  define WIN32_LEAN_AND_MEAN
-#  define _WINSOCKAPI_
-#  define WIN32_LEAN_AND_MEAN
 #  include <windows.h>
 #  ifdef _MSC_VER
 #    include <direct.h>

src/online/request_manager.cpp

@@ -30,6 +30,7 @@
 #include <errno.h>
 
 #if defined(WIN32) && !defined(__CYGWIN__)
+#  define WIN32_LEAN_AND_MEAN
 #  include <windows.h>
 #else
 #  include <sys/time.h>

src/utils/log.cpp

@@ -28,6 +28,7 @@
 #endif
 
 #ifdef WIN32
+#  define WIN32_LEAN_AND_MEAN
 #  include <windows.h>
 #endif
 

src/utils/profiler.cpp

@@ -74,6 +74,7 @@ Profiler profiler;
 
 // --- Begin portable precise timer ---
 #ifdef WIN32
+    #define WIN32_LEAN_AND_MEAN
     #include <windows.h>
 
     double getTimeMilliseconds()

src/utils/time.hpp

@@ -25,7 +25,6 @@
 
 #ifdef WIN32
 #  define WIN32_LEAN_AND_MEAN
-#  define _WINSOCKAPI_
 #  include <windows.h>
 #  include <time.h>
 #else