Don't compile libaapt with the build number

Only do that for the aapt binary itself. This will allow libaapt to be
converted to Soong.

Also remove a few lines that weren't doing anything: aaptCppflags was
never set, LOCAL_C_INCLUDES := $(LOCAL_PATH) is implied.

Test: m aapt
Test: aapt version
Change-Id: Ia3bcece14921417e1bfd3406630961c013bd497c
diff --git a/tools/aapt/Main.cpp b/tools/aapt/Main.cpp
index 417b7ae..d714687 100644
--- a/tools/aapt/Main.cpp
+++ b/tools/aapt/Main.cpp
@@ -20,6 +20,23 @@
 
 static const char* gProgName = "aapt";
 
+#ifndef AAPT_VERSION
+    #define AAPT_VERSION ""
+#endif
+
+/*
+ * Show version info.  All the cool kids do it.
+ */
+int doVersion(Bundle* bundle)
+{
+    if (bundle->getFileSpecCount() != 0) {
+        printf("(ignoring extra arguments)\n");
+    }
+    printf("Android Asset Packaging Tool, v0.2-" AAPT_VERSION "\n");
+
+    return 0;
+}
+
 /*
  * When running under Cygwin on Windows, this will convert slash-based
  * paths into back-slash-based ones. Otherwise the ApptAssets file comparisons