Sync documentation of archive_read_open_memory with reality.
diff --git a/libarchive/archive_read_open.3 b/libarchive/archive_read_open.3
index 0249456..2278ebc 100644
--- a/libarchive/archive_read_open.3
+++ b/libarchive/archive_read_open.3
@@ -67,7 +67,7 @@
.Fa "size_t block_size"
.Fc
.Ft int
-.Fn archive_read_open_memory "struct archive *" "void *buff" "size_t size"
+.Fn archive_read_open_memory "struct archive *" "const void *buff" "size_t size"
.Sh DESCRIPTION
.Bl -tag -compact -width indent
.It Fn archive_read_open
