SHA1_DIGEST_SIZE also available as a static constant

src/crypto/axtls_sha1.c

 	.name		= "sha1",
 	.ctxsize	= SHA1_CTX_SIZE,
 	.blocksize	= 64,
-	.digestsize	= SHA1_SIZE,
+	.digestsize	= SHA1_DIGEST_SIZE,
 	.init		= sha1_init,
 	.encode		= sha1_update,
 	.final		= sha1_final,

src/include/gpxe/sha1.h

 struct crypto_algorithm;
 
 #define SHA1_CTX_SIZE sizeof ( SHA1_CTX )
+#define SHA1_DIGEST_SIZE SHA1_SIZE
 
 extern struct crypto_algorithm sha1_algorithm;