pull in latest nblibs (to match buildrump.sh)

diff --git a/nblibs b/nblibs
index 76537737d40612c13a11ac703919ee484d0f8c73..88f38e2071cf26de12e675d8eec9da29c024a91c 160000 (submodule)
--- a/nblibs
+++ b/nblibs
@@ -1 +1 @@
-Subproject commit 76537737d40612c13a11ac703919ee484d0f8c73
+Subproject commit 88f38e2071cf26de12e675d8eec9da29c024a91c