Tag version 1.37.31 after LLVM 4.0.1 merge
diff --git a/emscripten-version.txt b/emscripten-version.txt
index d13163a..116163c 100644
--- a/emscripten-version.txt
+++ b/emscripten-version.txt
@@ -1 +1 @@
-"1.37.30"
+"1.37.31"