[gn build] Port e3b30bc

Author: llvmgnsyncbot

llvm/utils/gn/secondary/lld/MachO/BUILD.gn

@@ -27,6 +27,7 @@ static_library("MachO") {
     "Arch/ARM64Common.cpp",
     "Arch/ARM64_32.cpp",
     "Arch/X86_64.cpp",
+    "BPSectionOrderer.cpp",
     "ConcatOutputSection.cpp",
     "Driver.cpp",
     "DriverUtils.cpp",