[ELF] make KEEP command recognize file patterns

Differential revision: https://reviews.llvm.org/D25242

llvm-svn: 283305
diff --git a/lld/ELF/LinkerScript.h b/lld/ELF/LinkerScript.h
index 47b7b68..ac73d4e 100644
--- a/lld/ELF/LinkerScript.h
+++ b/lld/ELF/LinkerScript.h
@@ -184,7 +184,7 @@
 
   // List of section patterns specified with KEEP commands. They will
   // be kept even if they are unused and --gc-sections is specified.
-  std::vector<llvm::Regex *> KeptSections;
+  std::vector<InputSectionDescription *> KeptSections;
 };
 
 extern ScriptConfiguration *ScriptConfig;