Constify.
(cherry picked from commit 1abfa78a8ba714f7e47bd674db53dbe303cd1ce7)

crypto/evp/evp.h

diff --git a/crypto/evp/evp.h b/crypto/evp/evp.h
index 2b130c4..a5aa4c8 100644
--- a/crypto/evp/evp.h
+++ b/crypto/evp/evp.h
@@ -675,7 +675,7 @@
 __owur int	EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
 			const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey);
 __owur int	EVP_DigestVerifyFinal(EVP_MD_CTX *ctx,
-			unsigned char *sig, size_t siglen);
+			const unsigned char *sig, size_t siglen);
 
 __owur int	EVP_OpenInit(EVP_CIPHER_CTX *ctx,const EVP_CIPHER *type,
 		const unsigned char *ek, int ekl, const unsigned char *iv,

crypto/evp/m_sigver.c

diff --git a/crypto/evp/m_sigver.c b/crypto/evp/m_sigver.c
index 9f83d3e..bc5e132 100644
--- a/crypto/evp/m_sigver.c
+++ b/crypto/evp/m_sigver.c
@@ -205,7 +205,8 @@
 	return 1;
 	}
 
-int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, unsigned char *sig, size_t siglen)
+int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig,
+								size_t siglen)
 	{
 	unsigned char md[EVP_MAX_MD_SIZE];
 	int r;

doc/crypto/EVP_DigestVerifyInit.pod

diff --git a/doc/crypto/EVP_DigestVerifyInit.pod b/doc/crypto/EVP_DigestVerifyInit.pod
index f224488..c59866c 100644
--- a/doc/crypto/EVP_DigestVerifyInit.pod
+++ b/doc/crypto/EVP_DigestVerifyInit.pod
@@ -11,7 +11,7 @@
  int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
 			const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey);
  int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt);
- int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, unsigned char *sig, size_t siglen);
+ int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig, size_t siglen);
 
 =head1 DESCRIPTION