[AC21.5] Simplify redisplay-x/separate_textual_runs

[Stephen J. Turnbull]

Vin Shelton writes:

 > I think the attached patch broke non-mule display.  Please look at the
 > attached screenshot; I've also attached my Installation file.

Mea culpa.  Try this patch.

diff --git a/src/redisplay-x.c b/src/redisplay-x.c
index fe6c089..29d9912 100644
--- a/src/redisplay-x.c
+++ b/src/redisplay-x.c
@@ -145,7 +145,8 @@ separate_textual_runs_nomule (unsigned char *text_storage,
   run_storage[0].dimension = 1;
   run_storage[0].charset = Qnil;
 
-  memcpy (text_storage, str, len);
+  while (len--)
+    *text_storage++ = *str++;
   return 1;
 }
 #endif