Disable warning 40 by default.

This is one of the most commonly disabled warnings.

Author: jordwalke

package.json

@@ -35,7 +35,7 @@
 
     "postinstall": "npm run reasonBuild",
     "buildHelp": "eval $(dependencyEnv) && nopam && rebuild --help",
-    "reasonBuild": "eval $(dependencyEnv) && nopam && rebuild -use-ocamlfind -I src ./src/Test.native 2>&1 | refmterr",
+    "reasonBuild": "eval $(dependencyEnv) && nopam && rebuild -use-ocamlfind -cflag -w -cflag -40 -I src ./src/Test.native 2>&1 | refmterr",
     "reasonbuild": "npm run reasonBuild",
 
     "start": "eval $(dependencyEnv) && ./_build/src/Test.native",