diff --git a/vendor/github.com/pierrec/lz4/errors.go b/vendor/github.com/pierrec/lz4/errors.go
index 71a5a38..1c45d18 100644
--- a/vendor/github.com/pierrec/lz4/errors.go
+++ b/vendor/github.com/pierrec/lz4/errors.go
@@ -1,6 +1,11 @@
 package lz4
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+	"os"
+	rdebug "runtime/debug"
+)
 
 var (
 	// ErrInvalidSourceShortBuffer is returned by UncompressBlock or CompressBLock when a compressed
@@ -10,10 +15,16 @@
 	ErrInvalid = errors.New("lz4: bad magic number")
 	// ErrBlockDependency is returned when attempting to decompress an archive created with block dependency.
 	ErrBlockDependency = errors.New("lz4: block dependency not supported")
+	// ErrUnsupportedSeek is returned when attempting to Seek any way but forward from the current position.
+	ErrUnsupportedSeek = errors.New("lz4: can only seek forward from io.SeekCurrent")
 )
 
 func recoverBlock(e *error) {
-	if recover() != nil && *e == nil {
+	if r := recover(); r != nil && *e == nil {
+		if debugFlag {
+			fmt.Fprintln(os.Stderr, r)
+			rdebug.PrintStack()
+		}
 		*e = ErrInvalidSourceShortBuffer
 	}
 }