Don't assume size_t is either int- or long-sized.

On 64bit Windows systems, sizeof(int)==sizeof(long)=4, but size_t is 8
bytes large.

Fixes #12179.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64788 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/defs.h

@@ -929,10 +929,6 @@ typedef wxUint16 wxWord;
     #error "SIZEOF_WCHAR_T must be defined, but isn't"
 #endif
 
-#if !defined(wxSIZE_T_IS_UINT) && !defined(wxSIZE_T_IS_ULONG)
-    #error "wxSIZE_T_IS_UINT or wxSIZE_T_IS_ULONG must be defined"
-#endif
-
 /* also define C99-like sized MIN/MAX constants */
 #define wxINT8_MIN CHAR_MIN
 #define wxINT8_MAX CHAR_MAX