fixes to wint_t and wchar_t handling in unichar.h (fixes FreeBSD compilation and Mingw compilation with -pedantic)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46967 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

configure.in

@@ -4411,6 +4411,28 @@ else
     fi
 fi
 
+AC_CACHE_CHECK([if wchar_t is separate type],
+    wx_cv_wchar_t_is_separate_type,
+    AC_TRY_COMPILE([#include <wchar.h>],
+        [
+            return 0; }
+
+            struct Foo { void foo(wchar_t);
+                         void foo(unsigned short);
+                         void foo(unsigned int);
+                         void foo(unsigned long); };
+
+            int bar() {
+        ],
+        wx_cv_wchar_t_is_separate_type=yes,
+        wx_cv_wchar_t_is_separate_type=no
+    )
+)
+
+if test "$wx_cv_wchar_t_is_separate_type" = "yes"; then
+    AC_DEFINE(wxWCHAR_T_IS_SEPARATE_TYPE)
+fi
+
 AC_LANG_POP() dnl C++
 
 dnl ---------------------------------------------------------------------------