AAPT2: Variety of small fixes to get the build working

- Add option to rename package in AndroidManifest.xml
- Support default versionName and versionCode
- Accept True and False as valid booleans

Change-Id: I400e350b9dcd0fd1c197d1929144299c7823617d
diff --git a/tools/aapt2/util/Files.cpp b/tools/aapt2/util/Files.cpp
index a81dc7b..04e8199 100644
--- a/tools/aapt2/util/Files.cpp
+++ b/tools/aapt2/util/Files.cpp
@@ -163,6 +163,11 @@
     }
 
     android::FileMap fileMap;
+    if (fileStats.st_size == 0) {
+        // mmap doesn't like a length of 0. Instead we return an empty FileMap.
+        return std::move(fileMap);
+    }
+
     if (!fileMap.create(path.data(), fd, 0, fileStats.st_size, true)) {
         if (outError) *outError = strerror(errno);
         return {};