Error on trying to discard .dynamic.

We would crash instead before.

llvm-svn: 305613
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 8c7a1e7..651acea 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -338,8 +338,8 @@
 void LinkerScript::discard(ArrayRef<InputSectionBase *> V) {
   for (InputSectionBase *S : V) {
     S->Live = false;
-    if (S == InX::ShStrTab)
-      error("discarding .shstrtab section is not allowed");
+    if (S == InX::ShStrTab || S == InX::Dynamic)
+      error("discarding " + S->Name + " section is not allowed");
     discard(S->DependentSections);
   }
 }