Merge pull request #993 from yuriks/update-nihstro

Update nihstro to latest master.

externals/nihstro

@@ -1 +1 @@
-Subproject commit 81f1804a43f625e3a1a20752c0db70a413410380
+Subproject commit 676254f71e0a7ef0aca8acce078d3c3dc80ccf70