build: bump libbson for next_power_of_two().

Christian Hergert · Christian Hergert · commit 31338288fbee · 2014-06-04T14:19:20.000-04:00
diff --git a/src/libbson b/src/libbson
@@ -1 +1 @@
-Subproject commit 2fc0f1a1fafe5a90296673f99e146e5177bc483b
+Subproject commit 990449231758e8865eef9c8cc84c865c03a689ed
