Merge pull request #228 from sunfishcode/size_t-long

Bump version to 1.38.10, due to ABI changes.
diff --git a/emscripten-version.txt b/emscripten-version.txt
index e2d75e1..8c5d79d 100644
--- a/emscripten-version.txt
+++ b/emscripten-version.txt
@@ -1 +1 @@
-"1.38.9"
+"1.38.10"