Don't test for wide character functions in configure under OS X.

The tests for these functions may succeed on the system we're running under
but the functions may not be actually available on the system the application
is going to run under (if it's < 10.7).

So use our own replacements for these functions unless 10.7 was explicitly
chosen as the minimal possible version.

An alternative solution could have been to use weak linking but this is more
difficult and there is no real gain (performance would need to be measured
first).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74523 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/osx/config_xcode.h

@@ -74,6 +74,17 @@
 #define HAVE_VSSCANF_DECL 1
 #define HAVE_USLEEP 1
 #define HAVE_WCSLEN 1
+
+/* Many wchar functions are only available since 10.7 so don't use them if we
+   want to build the applications that would run under 10.6 and earlier. */
+#if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_7
+#define HAVE_WCSDUP 1
+#define HAVE_WCSFTIME 1
+#define HAVE_WCSNLEN 1
+#define HAVE_WCSCASECMP 1
+#define HAVE_WCSNCASECMP 1
+#endif
+
 #define SIZEOF_WCHAR_T 4
 #define SIZEOF_SHORT 2
 #define SIZEOF_INT 4