Clean up key handling in adb.

This includes the locking we need to be able to re-load the keys at runtime.

We should rename "adb_auth_client.cpp" to "adb_auth_adbd.cpp" or
"adbd_auth.cpp" in a later change.

Change-Id: I9e1d5b6b7d0497d6f6e5d9c4fb660118cdff05a8
Test: "adb devices" works against a non-AOSP device with $ADB_VENDOR_KEYS set, says "unauthorized" without.
Bug: http://b/29273531
diff --git a/adb/sysdeps.h b/adb/sysdeps.h
index 04df16f..333b861 100644
--- a/adb/sysdeps.h
+++ b/adb/sysdeps.h
@@ -828,4 +828,9 @@
 // configured to drop after 10 missed keepalives. Returns true on success.
 bool set_tcp_keepalive(int fd, int interval_sec);
 
+#if defined(_WIN32)
+// Win32 defines ERROR, which we don't need, but which conflicts with google3 logging.
+#undef ERROR
+#endif
+
 #endif /* _ADB_SYSDEPS_H */