Update wx to r75363 to address a wx bug that was breaking netplay on OS X.

Externals/wxWidgets3/include/wx/compiler.h

@@ -19,7 +19,7 @@
 /*
     Notice that Intel compiler can be used as Microsoft Visual C++ add-on and
     so we should define both __INTELC__ and __VISUALC__ for it.
- */
+*/
 #ifdef __INTEL_COMPILER
 #   define __INTELC__
 #endif
@@ -135,15 +135,40 @@
 #endif
 
 /*
-   This macro can be used to check that the version of mingw32 compiler is
-   at least maj.min
+   This macro can be used to check that the version of mingw32 CRT is at least
+   maj.min
  */
 
 /* Check for Mingw runtime version: */
-#if defined(__MINGW32_MAJOR_VERSION) && defined(__MINGW32_MINOR_VERSION)
+#ifdef __MINGW32__
+    /* Include the header defining __MINGW32_{MAJ,MIN}OR_VERSION */
+    #include <_mingw.h>
+
     #define wxCHECK_MINGW32_VERSION( major, minor ) \
  ( ( ( __MINGW32_MAJOR_VERSION > (major) ) \
       || ( __MINGW32_MAJOR_VERSION == (major) && __MINGW32_MINOR_VERSION >= (minor) ) ) )
+
+/*
+    MinGW-w64 project provides compilers for both Win32 and Win64 but only
+    defines the same __MINGW32__ symbol for the former as MinGW32 toolchain
+    which is quite different (notably doesn't provide many SDK headers that
+    MinGW-w64 does include). So we define a separate symbol which, unlike the
+    predefined __MINGW64__, can be used to detect this toolchain in both 32 and
+    64 bit builds.
+
+    And define __MINGW32_TOOLCHAIN__ for consistency and also because it's
+    convenient as we often want to have some workarounds only for the (old)
+    MinGW32 but not (newer) MinGW-w64, which still predefines __MINGW32__.
+ */
+#   ifdef __MINGW64_VERSION_MAJOR
+#       ifndef __MINGW64_TOOLCHAIN__
+#           define __MINGW64_TOOLCHAIN__
+#       endif
+#   else
+#       ifndef __MINGW32_TOOLCHAIN__
+#           define __MINGW32_TOOLCHAIN__
+#       endif
+#   endif
 #else
     #define wxCHECK_MINGW32_VERSION( major, minor ) (0)
 #endif