cmd/compile: remove syslook's copy parameter

Instead make substArgTypes responsible for cloning the function
definition Node and the function signature Type tree.

Passes toolstash -cmp.

Change-Id: I9ec84c90a7ae83d164d3f578e84a91cf1490d8ab
Reviewed-on: https://go-review.googlesource.com/20239
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 0a00846..d4f06f2 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -2778,7 +2778,7 @@
 	bElse := s.f.NewBlock(ssa.BlockPlain)
 	bEnd := s.f.NewBlock(ssa.BlockPlain)
 
-	aux := &ssa.ExternSymbol{Types[TBOOL], syslook("writeBarrier", 0).Sym}
+	aux := &ssa.ExternSymbol{Types[TBOOL], syslook("writeBarrier").Sym}
 	flagaddr := s.newValue1A(ssa.OpAddr, Ptrto(Types[TUINT32]), aux, s.sb)
 	// TODO: select the .enabled field. It is currently first, so not needed for now.
 	// Load word, test byte, avoiding partial register write from load byte.
@@ -2823,7 +2823,7 @@
 	bElse := s.f.NewBlock(ssa.BlockPlain)
 	bEnd := s.f.NewBlock(ssa.BlockPlain)
 
-	aux := &ssa.ExternSymbol{Types[TBOOL], syslook("writeBarrier", 0).Sym}
+	aux := &ssa.ExternSymbol{Types[TBOOL], syslook("writeBarrier").Sym}
 	flagaddr := s.newValue1A(ssa.OpAddr, Ptrto(Types[TUINT32]), aux, s.sb)
 	// TODO: select the .enabled field. It is currently first, so not needed for now.
 	// Load word, test byte, avoiding partial register write from load byte.