diff --git a/mailnews/base/src/nsMsgLocalMailFolder.cpp b/mailnews/base/src/nsMsgLocalMailFolder.cpp
index 04a88557612f..533ce066e6c2 100644
--- a/mailnews/base/src/nsMsgLocalMailFolder.cpp
+++ b/mailnews/base/src/nsMsgLocalMailFolder.cpp
@@ -23,6 +23,11 @@
 #include "prprf.h"
 #include "nsIRDFResourceFactory.h"
 
+// we need this because of an egcs 1.0 (and possibly gcc) compiler bug
+// that doesn't allow you to call ::nsISupports::IID() inside of a class
+// that multiply inherits from nsISupports
+static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
+
 nsMsgLocalMailFolder::nsMsgLocalMailFolder(const char* uri)
   :nsMsgFolder(uri)
 {
@@ -46,7 +51,7 @@ nsMsgLocalMailFolder::QueryInterface(REFNSIID iid, void** result)
 
 	*result = nsnull;
 	if (iid.Equals(nsIMsgLocalMailFolder::IID()) ||
-      iid.Equals(::nsISupports::IID()))
+      iid.Equals(kISupportsIID))
 	{
 		*result = NS_STATIC_CAST(nsIMsgLocalMailFolder*, this);
 		AddRef();
@@ -364,7 +369,8 @@ nsMsgLocalMailFolder::FindChildNamed(const char *name, nsIMsgFolder ** aChild)
     supports = mSubFolders->ElementAt(i);
 		if(folder)
 			NS_RELEASE(folder);
-		if(NS_SUCCEEDED(supports->QueryInterface(::nsISupports::IID(), (void**)&folder)))
+		if(NS_SUCCEEDED(supports->QueryInterface(kISupportsIID,
+                                             (void**)&folder)))
 		{
 			char *folderName;
 
diff --git a/mailnews/db/msgdb/src/nsDBFolderInfo.cpp b/mailnews/db/msgdb/src/nsDBFolderInfo.cpp
index 98d14977762f..c1290098f07d 100644
--- a/mailnews/db/msgdb/src/nsDBFolderInfo.cpp
+++ b/mailnews/db/msgdb/src/nsDBFolderInfo.cpp
@@ -39,7 +39,7 @@ static const char *	kUnreadPendingMessagesColumnName = "unreadPendingMsgs";
 static const char * kMailboxNameColumnName = "mailboxName";
 
 nsDBFolderInfo::nsDBFolderInfo(nsMsgDatabase *mdb)
-  : m_folderDate()      // now
+  : m_folderDate(0)      // now
 {
 	m_mdbTable = NULL;
 	m_mdbRow = NULL;
diff --git a/mailnews/local/src/nsMSGFolderDataSource.cpp b/mailnews/local/src/nsMSGFolderDataSource.cpp
index d47e5f75b8ad..c38d9a5a209e 100644
--- a/mailnews/local/src/nsMSGFolderDataSource.cpp
+++ b/mailnews/local/src/nsMSGFolderDataSource.cpp
@@ -40,6 +40,12 @@
 static NS_DEFINE_CID(kRDFServiceCID,							NS_RDFSERVICE_CID);
 static NS_DEFINE_CID(kRDFInMemoryDataSourceCID,		NS_RDFINMEMORYDATASOURCE_CID);
 
+// we need this because of an egcs 1.0 (and possibly gcc) compiler bug
+// that doesn't allow you to call ::nsISupports::IID() inside of a class
+// that multiply inherits from nsISupports
+static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
+static NS_DEFINE_IID(kIRDFCursorIID, NS_IRDFCURSOR_IID);
+
 nsIRDFResource* nsMSGFolderDataSource::kNC_Child;
 nsIRDFResource* nsMSGFolderDataSource::kNC_Folder;
 nsIRDFResource* nsMSGFolderDataSource::kNC_Name;
@@ -768,8 +774,8 @@ ArrayMsgFolderCursor::QueryInterface(REFNSIID iid, void** result)
 
   *result = nsnull;
   if (iid.Equals(nsIRDFAssertionCursor::IID()) ||
-      iid.Equals(::nsIRDFCursor::IID()) ||
-      iid.Equals(::nsISupports::IID())) {
+      iid.Equals(kIRDFCursorIID) ||
+      iid.Equals(kISupportsIID)) {
       *result = NS_STATIC_CAST(nsIRDFAssertionCursor*, this);
       AddRef();
       return NS_OK;
diff --git a/mailnews/local/src/nsMailboxUrl.cpp b/mailnews/local/src/nsMailboxUrl.cpp
index f2faf1ff072d..97a7cf36657e 100644
--- a/mailnews/local/src/nsMailboxUrl.cpp
+++ b/mailnews/local/src/nsMailboxUrl.cpp
@@ -34,6 +34,11 @@
 #include "prprf.h"
 #include "nsCRT.h"
 
+// we need this because of an egcs 1.0 (and possibly gcc) compiler bug
+// that doesn't allow you to call ::nsISupports::IID() inside of a class
+// that multiply inherits from nsISupports
+static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
+
 nsMailboxUrl::nsMailboxUrl(nsISupports* aContainer, nsIURLGroup* aGroup)
 {
     NS_INIT_REFCNT();
@@ -88,7 +93,8 @@ nsresult nsMailboxUrl::QueryInterface(const nsIID &aIID, void** aInstancePtr)
         return NS_ERROR_NULL_POINTER;
     }
  
-    if (aIID.Equals(nsIMailboxUrl::IID()) || aIID.Equals(::nsISupports::IID())) {
+    if (aIID.Equals(nsIMailboxUrl::IID()) ||
+        aIID.Equals(kISupportsIID)) {
         *aInstancePtr = (void*) ((nsIMailboxUrl*)this);
         NS_ADDREF_THIS();
         return NS_OK;
diff --git a/mailnews/local/src/nsPop3URL.cpp b/mailnews/local/src/nsPop3URL.cpp
index f0c6cd85dbd1..4dcd89e53e19 100644
--- a/mailnews/local/src/nsPop3URL.cpp
+++ b/mailnews/local/src/nsPop3URL.cpp
@@ -33,6 +33,12 @@
 #include "prprf.h"
 #include "nsCRT.h"
 
+// we need this because of an egcs 1.0 (and possibly gcc) compiler bug
+// that doesn't allow you to call ::nsISupports::IID() inside of a class
+// that multiply inherits from nsISupports
+static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
+
+
 nsPop3URL::nsPop3URL(nsISupports* aContainer, nsIURLGroup* aGroup)
 {
     NS_INIT_REFCNT();
@@ -86,7 +92,8 @@ nsresult nsPop3URL::QueryInterface(const nsIID &aIID, void** aInstancePtr)
         return NS_ERROR_NULL_POINTER;
     }
  
-    if (aIID.Equals(nsIPop3URL::IID()) || aIID.Equals(::nsISupports::IID())) {
+    if (aIID.Equals(nsIPop3URL::IID()) ||
+        aIID.Equals(kISupportsIID)) {
         *aInstancePtr = (void*) ((nsIPop3URL*)this);
         AddRef();
         return NS_OK;
diff --git a/mailnews/news/src/nsNntpUrl.cpp b/mailnews/news/src/nsNntpUrl.cpp
index bcd704fb0ebf..ae6c6dfaeeb0 100644
--- a/mailnews/news/src/nsNntpUrl.cpp
+++ b/mailnews/news/src/nsNntpUrl.cpp
@@ -33,6 +33,11 @@
 #include "prprf.h"
 #include "nsCRT.h"
 
+// we need this because of an egcs 1.0 (and possibly gcc) compiler bug
+// that doesn't allow you to call ::nsISupports::IID() inside of a class
+// that multiply inherits from nsISupports
+static NS_DEFINE_IID(kISupportsIID, NS_ISUPPORTS_IID);
+
 nsNntpUrl::nsNntpUrl(nsISupports* aContainer, nsIURLGroup* aGroup)
 {
     NS_INIT_REFCNT();
@@ -95,7 +100,8 @@ nsresult nsNntpUrl::QueryInterface(const nsIID &aIID, void** aInstancePtr)
         return NS_ERROR_NULL_POINTER;
     }
  
-    if (aIID.Equals(nsINntpUrl::IID()) || aIID.Equals(::nsISupports::IID())) {
+    if (aIID.Equals(nsINntpUrl::IID()) ||
+        aIID.Equals(kISupportsIID)) {
         *aInstancePtr = (void*) ((nsINntpUrl*)this);
         NS_ADDREF_THIS();
         return NS_OK;