https://bugs.gentoo.org/870466
--- a/sha1.h
+++ b/sha1.h
@@ -59,4 +59,7 @@
 void SHA1_Init_With_IV( SHA1_ctx*, const byte[ SHA1_DIGEST_BYTES ] );
 
+void SHA1_Transform(  word32 H[ SHA1_DIGEST_WORDS ],
+		      const byte M[ SHA1_INPUT_BYTES ] );
+
 #endif