Add EVP AES-128 CFB128 support via decrepit.

Change-Id: I37a438b5b4b18d18756ba4aeb9f8548caa333981
Reviewed-on: https://boringssl-review.googlesource.com/20384
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/include/openssl/cipher.h b/include/openssl/cipher.h
index a8dd63a..7fbee8b 100644
--- a/include/openssl/cipher.h
+++ b/include/openssl/cipher.h
@@ -410,6 +410,9 @@
 OPENSSL_EXPORT const EVP_CIPHER *EVP_aes_192_ctr(void);
 OPENSSL_EXPORT const EVP_CIPHER *EVP_aes_192_gcm(void);
 
+// EVP_aes_128_cfb128 is only available in decrepit.
+OPENSSL_EXPORT const EVP_CIPHER *EVP_aes_128_cfb128(void);
+
 
 // Private functions.