Index: src/OFMutableTarArchiveEntry.m
==================================================================
--- src/OFMutableTarArchiveEntry.m
+++ src/OFMutableTarArchiveEntry.m
@@ -24,10 +24,15 @@
 @implementation OFMutableTarArchiveEntry
 @dynamic fileName, POSIXPermissions, ownerAccountID, groupOwnerAccountID;
 @dynamic compressedSize, uncompressedSize, modificationDate, type;
 @dynamic targetFileName, ownerAccountName, groupOwnerAccountName, deviceMajor;
 @dynamic deviceMinor;
+/*
+ * The following is optional in OFMutableArchiveEntry, but Apple GCC 4.0.1 is
+ * buggy and needs this to stop complaining.
+ */
+@dynamic fileComment;
 
 + (instancetype)entryWithFileName: (OFString *)fileName
 {
 	return [[[self alloc] initWithFileName: fileName] autorelease];
 }

Index: src/OFMutableZIPArchiveEntry.m
==================================================================
--- src/OFMutableZIPArchiveEntry.m
+++ src/OFMutableZIPArchiveEntry.m
@@ -27,10 +27,16 @@
 @implementation OFMutableZIPArchiveEntry
 @dynamic fileName, fileComment, extraField, versionMadeBy, minVersionNeeded;
 @dynamic modificationDate, compressionMethod, compressedSize, uncompressedSize;
 @dynamic CRC32, versionSpecificAttributes, generalPurposeBitFlag;
 @dynamic of_localFileHeaderOffset;
+/*
+ * The following are optional in OFMutableArchiveEntry, but Apple GCC 4.0.1 is
+ * buggy and needs this to stop complaining.
+ */
+@dynamic POSIXPermissions, ownerAccountID, groupOwnerAccountID;
+@dynamic ownerAccountName, groupOwnerAccountName;
 
 + (instancetype)entryWithFileName: (OFString *)fileName
 {
 	return [[[self alloc] initWithFileName: fileName] autorelease];
 }

Index: src/OFTarArchiveEntry.m
==================================================================
--- src/OFTarArchiveEntry.m
+++ src/OFTarArchiveEntry.m
@@ -73,10 +73,16 @@
 
 	return value;
 }
 
 @implementation OFTarArchiveEntry
+/*
+ * The following is optional in OFArchiveEntry, but Apple GCC 4.0.1 is buggy
+ * and needs this to stop complaining.
+ */
+@dynamic fileComment;
+
 - (instancetype)init
 {
 	OF_INVALID_INIT_METHOD
 }
 

Index: src/OFZIPArchiveEntry.m
==================================================================
--- src/OFZIPArchiveEntry.m
+++ src/OFZIPArchiveEntry.m
@@ -170,10 +170,17 @@
 	*size = 0;
 	return OFNotFound;
 }
 
 @implementation OFZIPArchiveEntry
+/*
+ * The following are optional in OFArchiveEntry, but Apple GCC 4.0.1 is buggy
+ * and needs this to stop complaining.
+ */
+@dynamic POSIXPermissions, ownerAccountID, groupOwnerAccountID;
+@dynamic ownerAccountName, groupOwnerAccountName;
+
 - (instancetype)init
 {
 	OF_INVALID_INIT_METHOD
 }