diff --git a/mozilla/caps/src/nsZip.c b/mozilla/caps/src/nsZip.c
index cdd4a1b5d99..3b964796819 100644
--- a/mozilla/caps/src/nsZip.c
+++ b/mozilla/caps/src/nsZip.c
@@ -39,6 +39,10 @@
 #include <stat.h>
 #endif
 
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>  /* for SEEK_SET and SEEK_END on some platforms */
+#endif
+
 #include "prlog.h"
 #include "prio.h"
 #include "prdtoa.h"
diff --git a/mozilla/network/protocol/file/mkfile.c b/mozilla/network/protocol/file/mkfile.c
index 2e7b062a18d..c4761f63c88 100644
--- a/mozilla/network/protocol/file/mkfile.c
+++ b/mozilla/network/protocol/file/mkfile.c
@@ -61,6 +61,10 @@ extern void ProcessCookiesAndTrustLabels( ActiveEntry *ce );
 #include "progress.h"
 #endif
 
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>  /* for SEEK_SET on some platforms */
+#endif
+
 /* for XP_GetString() */
 #include "xpgetstr.h"
 extern int XP_ALERT_OUTMEMORY;