add support for hidden visibility to darwin/x86

llvm-svn: 33198
diff --git a/llvm/lib/Target/X86/X86TargetAsmInfo.cpp b/llvm/lib/Target/X86/X86TargetAsmInfo.cpp
index 7371161..5d52d93 100644
--- a/llvm/lib/Target/X86/X86TargetAsmInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetAsmInfo.cpp
@@ -64,6 +64,7 @@
     SetDirective = "\t.set";
     UsedDirective = "\t.no_dead_strip\t";
     WeakRefDirective = "\t.weak_reference\t";
+    HiddenDirective = "\t.private_extern\t";
     
     NeedsSet = true;
     DwarfAbbrevSection = ".section __DWARF,__debug_abbrev,regular,debug";