Fix build with llvm22

Index: SOPE/GDLContentStore/GCSFolder.m
--- SOPE/GDLContentStore/GCSFolder.m.orig
+++ SOPE/GDLContentStore/GCSFolder.m
@@ -1146,7 +1146,7 @@ andAttribute: (EOAttribute *)_attribute
         // Update c_startdate for appointments
         if ([theComponent respondsToSelector:@selector(startDate)]) {
           NSTimeInterval t;
-          startDate = [theComponent startDate];
+          startDate = (NSCalendarDate*) [theComponent startDate];
           t = [startDate timeIntervalSince1970];
           if (startDate) {
             if (t < (long long)INT_MAX && t > (long long)INT_MIN) {
