Resolve compile warnings with Forte.

* subversion/libsvn_ra_svn/cram.c (hex_encode, svn_ra_svn__cram_client),
  subversion/libsvn_fs_fs/fs_fs.c (write_hash_rep): apr_md5_* takes in
  unsigned chars.
* subversion/libsvn_delta/svndiff.c: Weakly resolve mismatch between
  svn_stream_read and decode_window.

Index: subversion/libsvn_ra_svn/cram.c
===================================================================
--- subversion/libsvn_ra_svn/cram.c	(revision 9884)
+++ subversion/libsvn_ra_svn/cram.c	(working copy)
@@ -64,7 +64,7 @@
   return TRUE;
 }
 
-static void hex_encode(char *hexval, const char *hashval)
+static void hex_encode(unsigned char *hexval, const unsigned char *hashval)
 {
   int i;
 
@@ -180,7 +180,7 @@
                                      const char **message)
 {
   const char *status, *str, *reply;
-  char digest[APR_MD5_DIGESTSIZE], hex[2 * APR_MD5_DIGESTSIZE + 1];
+  unsigned char digest[APR_MD5_DIGESTSIZE], hex[2 * APR_MD5_DIGESTSIZE + 1];
 
   /* Read the server challenge. */
   SVN_ERR(svn_ra_svn_read_tuple(conn, pool, "w(?c)", &status, &str));
Index: subversion/libsvn_delta/svndiff.c
===================================================================
--- subversion/libsvn_delta/svndiff.c	(revision 9884)
+++ subversion/libsvn_delta/svndiff.c	(working copy)
@@ -689,7 +689,7 @@
 {
   svn_filesize_t sview_offset;
   apr_size_t sview_len, tview_len, inslen, newlen, len;
-  unsigned char *buf;
+  char *buf;
 
   SVN_ERR (read_window_header (stream, &sview_offset, &sview_len, &tview_len,
                                &inslen, &newlen));
@@ -701,7 +701,7 @@
                              "Unexpected end of svndiff input");
   *window = apr_palloc (pool, sizeof(**window));
   SVN_ERR (decode_window (*window, sview_offset, sview_len, tview_len, inslen,
-                          newlen, buf, pool));
+                          newlen, (unsigned char*)buf, pool));
   return SVN_NO_ERROR;
 }
 
Index: subversion/libsvn_fs_fs/fs_fs.c
===================================================================
--- subversion/libsvn_fs_fs/fs_fs.c	(revision 9884)
+++ subversion/libsvn_fs_fs/fs_fs.c	(working copy)
@@ -3011,7 +3011,7 @@
    md5 digest in CHECKSUM.  Perform temporary allocations in POOL. */
 static svn_error_t *
 write_hash_rep (apr_size_t *size,
-                char checksum[APR_MD5_DIGESTSIZE],
+                unsigned char checksum[APR_MD5_DIGESTSIZE],
                 apr_file_t *file,
                 apr_hash_t *hash,
                 apr_pool_t *pool)