Improve compatibility detection for <time.h> and <sys/stat.h>: 
- Move <time.h> before other includes on Windows, so we are sure the time_t definition being checked doesn't come from <sys/types.h>. 
- Padding at the end of Tcl_StatBuf doesn't influcence binary compatibility, so relax panic check accordingly.
Improve compatibility detection for <time.h> and <sys/stat.h>: 
- Move <time.h> before other includes on Windows, so we are sure the time_t definition being checked doesn't come from <sys/types.h>. 
- Padding at the end of Tcl_StatBuf doesn't influcence binary compatibility, so relax panic check accordingly.
merge trunk