Fixed const correctness issues that have no impact on the ABI
(cherry picked from commit eae09db9e57b7a342ea15bf57c5c1439c59a2e50)

Conflicts:
	library/gcm.c
diff --git a/library/sha2.c b/library/sha2.c
index af3a6ee..7b375ff 100644
--- a/library/sha2.c
+++ b/library/sha2.c
@@ -250,8 +250,7 @@
 
     if( left && ilen >= fill )
     {
-        memcpy( (void *) (ctx->buffer + left),
-                (void *) input, fill );
+        memcpy( (void *) (ctx->buffer + left), input, fill );
         sha2_process( ctx, ctx->buffer );
         input += fill;
         ilen  -= fill;
@@ -266,10 +265,7 @@
     }
 
     if( ilen > 0 )
-    {
-        memcpy( (void *) (ctx->buffer + left),
-                (void *) input, ilen );
-    }
+        memcpy( (void *) (ctx->buffer + left), input, ilen );
 }
 
 static const unsigned char sha2_padding[64] =
@@ -299,7 +295,7 @@
     last = ctx->total[0] & 0x3F;
     padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
 
-    sha2_update( ctx, (unsigned char *) sha2_padding, padn );
+    sha2_update( ctx, sha2_padding, padn );
     sha2_update( ctx, msglen, 8 );
 
     PUT_UINT32_BE( ctx->state[0], output,  0 );