check-flagged-apis: add support for command line options

Use clikt as the command line options parser library.

Bug: 334870672
Test: m check-flagged-apis && check-flagged-apis
Change-Id: I7c406456b00e29293294dcdbef411d2543a1e8d5

tools/check-flagged-apis/Android.bp

@@ -21,5 +21,8 @@ java_binary_host {
     srcs: [
         "src/**/*.kt",
     ],
+    static_libs: [
+        "metalava-tools-common-m2-deps",
+    ],
     main_class: "com.android.checkflaggedapis.Main",
 }

tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt

@@ -17,4 +17,14 @@
 
 package com.android.checkflaggedapis
 
-fun main() = println("hello world")
+import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.core.ProgramResult
+
+class CheckCommand : CliktCommand() {
+  override fun run() {
+    println("hello world")
+    throw ProgramResult(0)
+  }
+}
+
+fun main(args: Array<String>) = CheckCommand().main(args)