Installd: Amend dexopt binder logging

Add an enum for all exit codes used inside dexopt.cpp. Use the dex2oat
return-codes enum for dex2oat exec results. Add a function to map
these enum cases to small string snippets.

Test: mmma frameworks/native/cmds/installd
Test: installd_dexopt_test
Change-Id: I840ecbcaeb3ec1dcd9bd37dff9bdea35202b4731
diff --git a/cmds/installd/Android.bp b/cmds/installd/Android.bp
index 352cf0a..94c3102 100644
--- a/cmds/installd/Android.bp
+++ b/cmds/installd/Android.bp
@@ -5,6 +5,10 @@
         "-Wall",
         "-Werror",
         "-Wextra",
+
+        "-Wunreachable-code",
+        "-Wunreachable-code-break",
+        "-Wunreachable-code-return",
     ],
     srcs: [
         "CacheItem.cpp",
@@ -15,6 +19,9 @@
         "utils.cpp",
         ":installd_aidl",
     ],
+    header_libs: [
+        "dex2oat_headers",
+    ],
     shared_libs: [
         "libbase",
         "libbinder",