[gcr] Fix incorrect loop condition in egg_hkdf_perform()

[Stefan Walter <stefw src gnome org>]

commit ce0f9c79382830a50d19f0d66d1997476950074a
Author: Xi Wang <xi wang gmail com>
Date:   Mon Oct 22 16:09:46 2012 -0400

    Fix incorrect loop condition in egg_hkdf_perform()
    
    This does not cause a change in behavior (as evidenced by tests,
    at least on linux when built with gcc) but is more correct code,
    and less likely to be miscompiled.
    
    The condition (i < 256) in the following loop is always false since i
    is of type guchar, which is at most 255.
    
    	guchar i;
    	...
    	for (i = 1; i < 256; ++i) { ... }
    
    This patch changes i to a larger type gint.
    
    Also in the loop we have:
    
    	gcry_md_write (md2, &i, 1);
    
    change it to use gcry_md_putc().

 egg/egg-hkdf.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/egg/egg-hkdf.c b/egg/egg-hkdf.c
index 2e34489..c6559de 100644
--- a/egg/egg-hkdf.c
+++ b/egg/egg-hkdf.c
@@ -39,7 +39,7 @@ egg_hkdf_perform (const gchar *hash_algo, gconstpointer input, gsize n_input,
 	gpointer buffer = NULL;
 	gcry_md_hd_t md1, md2;
 	guint hash_len;
-	guchar i;
+	gint i;
 	gint flags, algo;
 	gsize step, n_buffer;
 	guchar *at;
@@ -89,7 +89,7 @@ egg_hkdf_perform (const gchar *hash_algo, gconstpointer input, gsize n_input,
 		gcry_md_reset (md2);
 		gcry_md_write (md2, buffer, n_buffer);
 		gcry_md_write (md2, info, n_info);
-		gcry_md_write (md2, &i, 1);
+		gcry_md_putc (md2, i);
 
 		n_buffer = hash_len;
 		memcpy (buffer, gcry_md_read (md2, algo), n_buffer);