Add a pile of compatibility functions.

Change-Id: I75c8783139c717be34a9159a2291d2ae55ee71d5
Reviewed-on: https://boringssl-review.googlesource.com/30984
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/crypto.h b/include/openssl/crypto.h
index 8e1a271..d35cf71 100644
--- a/include/openssl/crypto.h
+++ b/include/openssl/crypto.h
@@ -125,6 +125,9 @@
 OPENSSL_EXPORT int OPENSSL_init_crypto(uint64_t opts,
                                        const OPENSSL_INIT_SETTINGS *settings);
 
+// OPENSSL_cleanup does nothing.
+OPENSSL_EXPORT void OPENSSL_cleanup(void);
+
 // FIPS_mode_set returns one if |on| matches whether BoringSSL was built with
 // |BORINGSSL_FIPS| and zero otherwise.
 OPENSSL_EXPORT int FIPS_mode_set(int on);