libdl/archive: Fix the config file string index while removing tailing white space.

Coverity issue 1442540

Updates #3686

cpukit/include/rtems/rtl/rtl-archive.h

@@ -103,7 +103,7 @@ typedef struct rtems_rtl_archives
   const char*         config_name;    /**< Config file name. */
   time_t              config_mtime;   /**< Config last modified time. */
   size_t              config_length;  /**< Length the config data. */
-  const char*         config;         /**< Config file contents. */
+  char*               config;         /**< Config file contents. */
   rtems_chain_control archives;       /**< The located archives. */
 } rtems_rtl_archives;
 

cpukit/libdl/rtl-archive.c

@@ -528,9 +528,9 @@ rtems_rtl_archives_load_config (rtems_rtl_archives* archives)
           ++b;
         }
         b = ls - 1;
-        while (b > 0 && isspace (s[b]))
+        while (b > 0 && isspace (s[r + b]))
         {
-          s[b] = '\0';
+          s[r + b] = '\0';
           --b;
         }
         r += ls;