gn build: Merge r372712

llvm-svn: 372713

Author: llvmgnsyncbot

llvm/utils/gn/secondary/llvm/tools/llvm-objcopy/BUILD.gn

@@ -54,6 +54,7 @@ executable("llvm-objcopy") {
     "COFF/Reader.cpp",
     "COFF/Writer.cpp",
     "CopyConfig.cpp",
+    "ELF/ELFConfig.cpp",
     "ELF/ELFObjcopy.cpp",
     "ELF/Object.cpp",
     "MachO/MachOLayoutBuilder.cpp",