Use wxINT32_MAX instead of LONG_MAX as the upper bound in wxDateTime::IsInStdRange().

Under Debian Linux 64 bit time_t is 64 bit long but libc doesn't seem to handle values beyond 2^32
correctly, e.g. wrong results are returned from localtime() for them. And it would seem that platforms
where sizeof(long) > sizeof(time_t) might exist too so it seems safer to only work with 32 bit time_t
values until we can reliably detect platforms which support 64 bit ones.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@61497 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/datetime.h

@@ -1722,7 +1722,9 @@ protected:
 
 inline bool wxDateTime::IsInStdRange() const
 {
-    return m_time >= 0l && (m_time / TIME_T_FACTOR) < LONG_MAX;
+    // currently we don't know what is the real type of time_t so prefer to err
+    // on the safe side and limit it to 32 bit values which is safe everywhere
+    return m_time >= 0l && (m_time / TIME_T_FACTOR) < wxINT32_MAX;
 }
 
 /* static */