binder: make recovery_available.

Test: builds
Bug: 170338625
Change-Id: Ifdf86483e78094a9ce20d48299a9b0c00f2e0758
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index 07555f6..7a30ff9 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -602,6 +602,8 @@
 
 #if defined(__ANDROID_VNDK__)
 constexpr int32_t kHeader = B_PACK_CHARS('V', 'N', 'D', 'R');
+#elif defined(__ANDROID_RECOVERY__)
+constexpr int32_t kHeader = B_PACK_CHARS('R', 'E', 'C', 'O');
 #else
 constexpr int32_t kHeader = B_PACK_CHARS('S', 'Y', 'S', 'T');
 #endif