Add |EVP_dss1| as an alias for |EVP_sha1| in decrepit.

Change-Id: I51fa744c367d1f0c7044050f99c4992778e649bd
Reviewed-on: https://boringssl-review.googlesource.com/8030
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/include/openssl/digest.h b/include/openssl/digest.h
index db3ead7..07ea07a 100644
--- a/include/openssl/digest.h
+++ b/include/openssl/digest.h
@@ -212,6 +212,12 @@
  * |name|, or NULL if the name is unknown. */
 OPENSSL_EXPORT const EVP_MD *EVP_get_digestbyname(const char *);
 
+/* EVP_dss1 returns the value of EVP_sha1(). This was provided by OpenSSL to
+ * specifiy the original DSA signatures, which were fixed to use SHA-1. Note,
+ * however, that attempting to sign or verify DSA signatures with the EVP
+ * interface will always fail. */
+OPENSSL_EXPORT const EVP_MD *EVP_dss1(void);
+
 
 /* Digest operation accessors. */