Include values in error message.

Bug: 112554546
Test: N/A
Change-Id: I56c468a9a4f162f6ce8079d6b4b61c5ec4b8f633
diff --git a/tools/aapt2/format/Container.cpp b/tools/aapt2/format/Container.cpp
index 739555c..d4b4571 100644
--- a/tools/aapt2/format/Container.cpp
+++ b/tools/aapt2/format/Container.cpp
@@ -270,7 +270,8 @@
   }
 
   if (magic != kContainerFormatMagic) {
-    error_ = "magic value doesn't match AAPT";
+    error_ =
+        StringPrintf("magic value is 0x%08x but AAPT expects 0x%08x", magic, kContainerFormatMagic);
     return;
   }