Constification.

crypto/pem/pem.h

diff --git a/crypto/pem/pem.h b/crypto/pem/pem.h
index 01dcde7..5fb903e 100644
--- a/crypto/pem/pem.h
+++ b/crypto/pem/pem.h
@@ -411,8 +411,8 @@
 #ifndef OPENSSL_NO_BIO
 int	PEM_read_bio(BIO *bp, char **name, char **header,
 		unsigned char **data,long *len);
-int	PEM_write_bio(BIO *bp,const char *name,char *hdr,unsigned char *data,
-		long len);
+int	PEM_write_bio(BIO *bp,const char *name, const char *hdr,
+		      const unsigned char *data, long len);
 int PEM_bytes_read_bio(unsigned char **pdata, long *plen, char **pnm, const char *name, BIO *bp,
 	     pem_password_cb *cb, void *u);
 void *	PEM_ASN1_read_bio(d2i_of_void *d2i, const char *name, BIO *bp,
@@ -428,7 +428,8 @@
 
 int	PEM_read(FILE *fp, char **name, char **header,
 		unsigned char **data,long *len);
-int	PEM_write(FILE *fp,char *name,char *hdr,unsigned char *data,long len);
+int	PEM_write(FILE *fp, const char *name, const char *hdr,
+		  const unsigned char *data, long len);
 void *  PEM_ASN1_read(d2i_of_void *d2i, const char *name, FILE *fp, void **x,
 		      pem_password_cb *cb, void *u);
 int	PEM_ASN1_write(i2d_of_void *i2d,const char *name,FILE *fp,

crypto/pem/pem_lib.c

diff --git a/crypto/pem/pem_lib.c b/crypto/pem/pem_lib.c
index 9e551d1..5e41d85 100644
--- a/crypto/pem/pem_lib.c
+++ b/crypto/pem/pem_lib.c
@@ -576,8 +576,8 @@
 	}
 
 #ifndef OPENSSL_NO_FP_API
-int PEM_write(FILE *fp, char *name, char *header, unsigned char *data,
-	     long len)
+int PEM_write(FILE *fp, const char *name, const char *header,
+	      const unsigned char *data, long len)
         {
         BIO *b;
         int ret;
@@ -594,8 +594,8 @@
         }
 #endif
 
-int PEM_write_bio(BIO *bp, const char *name, char *header, unsigned char *data,
-	     long len)
+int PEM_write_bio(BIO *bp, const char *name, const char *header,
+		  const unsigned char *data, long len)
 	{
 	int nlen,n,i,j,outl;
 	unsigned char *buf = NULL;