[MIPS] Initial checkin for MIPS changes for GOLD.

gold/output.h

Index: gold/output.h
===================================================================
--- a/gold/output.h
+++ b/gold/output.h
@@ -2424,6 +2424,11 @@
   add_string(elfcpp::DT tag, const std::string& str)
   { this->add_string(tag, str.c_str()); }
 
+  // Add a new dynamic entry with target specific value.
+  void
+  add_target_specific(elfcpp::DT tag)
+  { this->add_entry(Dynamic_entry(tag)); }
+
  protected:
   // Adjust the output section to set the entry size.
   void
@@ -2488,6 +2493,11 @@
       : tag_(tag), offset_(DYNAMIC_STRING)
     { this->u_.str = str; }
 
+    // Create an entry with a target specific value.
+    Dynamic_entry(elfcpp::DT tag)
+      : tag_(tag), offset_(DYNAMIC_TARGET)
+    { };
+
     // Return the tag of this entry.
     elfcpp::DT
     tag() const
@@ -2511,7 +2521,9 @@
       // Symbol adress.
       DYNAMIC_SYMBOL = -3U,
       // String.
-      DYNAMIC_STRING = -4U
+      DYNAMIC_STRING = -4U,
+      // Target specific value.
+      DYNAMIC_TARGET = -5U
       // Any other value indicates a section address plus OFFSET.
     };