BUG# 10687 - MERGE engine fails under Windows

This patch was submitted by Ingo and it appears to work correctly.

sql/ha_myisammrg.cc

@@ -406,8 +406,8 @@ int ha_myisammrg::create(const char *name, register TABLE *form,
         This means that it might not be possible to move the DATADIR of
         an embedded server without changing the paths in the .MRG file.
       */
-      uint length= my_snprintf(buff, FN_REFLEN, "%s/%s/%s", mysql_data_home,
-			       tables->db, tables->real_name);
+      uint length= my_snprintf(buff, FN_REFLEN, "%s%c%s/%s", mysql_data_home,
+			       FN_LIBCHAR, tables->db, tables->real_name);
       /*
         If a MyISAM table is in the same directory as the MERGE table,
         we use the table name without a path. This means that the
@@ -422,6 +422,7 @@ int ha_myisammrg::create(const char *name, register TABLE *form,
     }
     else
       table_name=(*tbl)->path;
+    DBUG_PRINT("info",("MyISAM table_name: '%s'", table_name));
     *pos++= table_name;
   }
   *pos=0;

strings/my_vsnprintf.c

@@ -28,7 +28,8 @@
     %#[l]u
     %#[l]x
     %#.#s	Note first # is ignored
-
+    %c
+    
   RETURN
     length of result string
 */
@@ -120,6 +121,11 @@ int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap)
       to+= res_length;
       continue;
     }
+    else if (*fmt == 'c')
+    {
+      *(to++)= (char) va_arg(ap, int);
+      continue;
+    }
     /* We come here on '%%', unknown code or too long parameter */
     if (to == end)
       break;