Fix internal error when relaxing branches to STT_SECTION symbols.

gold/
	PR gold/20807
	* aarch64.cc (Target_aarch64::scan_reloc_section_for_stubs): Handle
	section symbols correctly.
	* arm.cc (Target_arm): Likewise.
	* powerpc.cc (Target_powerpc): Likewise.
diff --git a/gold/ChangeLog b/gold/ChangeLog
index 8e897f8..39536ac 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,6 +1,13 @@
 2017-02-22  Alan Modra  <amodra@gmail.com>
 
 	Apply from master
+	2016-12-01  Cary Coutant  <ccoutant@gmail.com>
+	PR gold/20807
+	* aarch64.cc (Target_aarch64::scan_reloc_section_for_stubs): Handle
+	section symbols correctly.
+	* arm.cc (Target_arm): Likewise.
+	* powerpc.cc (Target_powerpc): Likewise.
+
 	2016-08-31  Alan Modra  <amodra@gmail.com>
 	* powerpc.cc (class Stub_control): Delete stub14_group_size_
 	and has14_.  Add group_size_.
diff --git a/gold/aarch64.cc b/gold/aarch64.cc
index db9f06c..f31e091 100644
--- a/gold/aarch64.cc
+++ b/gold/aarch64.cc
@@ -3865,6 +3865,8 @@
 	  if (!is_defined_in_discarded_section)
 	    {
 	      typedef Sized_relobj_file<size, big_endian> ObjType;
+	      if (psymval->is_section_symbol())
+		symval.set_is_section_symbol();
 	      typename ObjType::Compute_final_local_value_status status =
 		object->compute_final_local_value(r_sym, psymval, &symval,
 						  relinfo->symtab);
diff --git a/gold/arm.cc b/gold/arm.cc
index c47b002..9120279 100644
--- a/gold/arm.cc
+++ b/gold/arm.cc
@@ -11998,6 +11998,8 @@
 	  if (!is_defined_in_discarded_section)
 	    {
 	      typedef Sized_relobj_file<32, big_endian> ObjType;
+	      if (psymval->is_section_symbol())
+		symval.set_is_section_symbol();
 	      typename ObjType::Compute_final_local_value_status status =
 		arm_object->compute_final_local_value(r_sym, psymval, &symval,
 						      relinfo->symtab);
diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index 8f5d259..2e85530 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -2799,6 +2799,8 @@
 	  const Symbol_value<size>* psymval
 	    = this->object_->local_symbol(this->r_sym_);
 	  Symbol_value<size> symval;
+	  if (psymval->is_section_symbol())
+	    symval.set_is_section_symbol();
 	  typedef Sized_relobj_file<size, big_endian> ObjType;
 	  typename ObjType::Compute_final_local_value_status status
 	    = this->object_->compute_final_local_value(this->r_sym_, psymval,