change the schema to support ppx arguments

Author: bobzhang

docs/docson/build-schema.json

@@ -67,7 +67,18 @@
         "ppx-specs": {
             "type": "array",
             "items": {
-                "type": "string"
+                "oneOf" : [
+                    {
+                        "type": "string"
+                    },
+                    {
+                        "type" : "array",
+                        "items": {
+                            "type" : "string"
+                        }
+                    }
+                ]
+                
             }
         },
         "pp-specs": {

jscomp/build_tests/scoped_ppx/bsconfig.json

@@ -1,5 +1,10 @@
 {
-    "ppx-flags": ["@hongbo/ppx1/test.js"],
+    "ppx-flags": 
+        [
+            ["@hongbo/ppx1/test.js", "-hello"],
+            ["@hongbo/ppx1/test.js", "-heyy"],
+            "@hongbo/ppx1/test.js"
+        ],
     "sources" : {
         "dir": "src"
     },

jscomp/build_tests/scoped_ppx/input.js

@@ -1,3 +1,10 @@
-var cp = require('child_process')
+var cp = require("child_process");
+var assert = require('assert')
+cp.execSync(`bsb`, { cwd: __dirname, stdio: [0, 1, 2], encoding: "utf8" });
+
+var output = cp.execSync(`bsb -- -t commands src/hello.mlast`, {
+  cwd: __dirname,
+  encoding: "utf8"
+});
+assert(/-ppx '.*\/test\.js -hello' -ppx '.*\/test\.js -heyy' -ppx .*test\.js/.test(output))
 
-cp.execSync(`bsb -regen`)