diff --git a/mozilla/xpcom/MoreFiles/MoreFilesX.c b/mozilla/xpcom/MoreFiles/MoreFilesX.c
index 7934f8ea130..9f3762c2c0e 100644
--- a/mozilla/xpcom/MoreFiles/MoreFilesX.c
+++ b/mozilla/xpcom/MoreFiles/MoreFilesX.c
@@ -2316,11 +2316,12 @@ BadParameter:
 
 /*****************************************************************************/
 
-// This function exists in Mac OS X 10.5, we cannot re-define it here.
-// We don't use this function, so just don't compile it.
-#if 0
+/* Renamed from FSVolumeMount to MFX_FSVolumeMount to avoid a conflict with
+ * the FSVolumeMount function present in the system library since Mac OS X
+ * 10.5. */
+
 OSErr
-FSVolumeMount(
+MFX_FSVolumeMount(
 	const void *volMountInfo,
 	FSVolumeRefNum *volRefNum)
 {
@@ -2342,7 +2343,6 @@ BadParameter:
 
 	return ( result );
 }
-#endif
 
 /*****************************************************************************/
 
diff --git a/mozilla/xpcom/MoreFiles/MoreFilesX.h b/mozilla/xpcom/MoreFiles/MoreFilesX.h
index 66821dff004..285fa08efe6 100644
--- a/mozilla/xpcom/MoreFiles/MoreFilesX.h
+++ b/mozilla/xpcom/MoreFiles/MoreFilesX.h
@@ -1489,15 +1489,14 @@ FSGetVolMountInfo(
 /*****************************************************************************/
 
 #pragma mark FSVolumeMount
+/* Renamed from FSVolumeMount to MFX_FSVolumeMount to avoid a conflict with
+ * the FSVolumeMount function present in the system library since Mac OS X
+ * 10.5. */
 
-// This function exists in Mac OS X 10.5, we cannot re-define it here.
-// We don't use this function, so just don't compile it.
-#if 0
 OSErr
-FSVolumeMount(
+MFX_FSVolumeMount(
 	const void *volMountInfo,
 	FSVolumeRefNum *volRefNum);
-#endif
 
 /*
 	The VolumeMount function mounts a volume using a volume mounting