Update pdclib to version using arm-specific 'ar' program

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/pdclib b/pdclib
index bd33f6640cf5882f8630766a9acdd1bc420a9dda..3e68419ad3ca3237ca16de4cf2a967f04129fe33 160000 (submodule)
--- a/pdclib
+++ b/pdclib
@@ -1 +1 @@
-Subproject commit bd33f6640cf5882f8630766a9acdd1bc420a9dda
+Subproject commit 3e68419ad3ca3237ca16de4cf2a967f04129fe33