Add debug support for X86/ELF targets (Linux). This allows llvm-gcc4
generated object modules to be debugged with gdb. Hopefully this helps
pre-release debugging.

llvm-svn: 31299
diff --git a/llvm/lib/Target/X86/X86AsmPrinter.h b/llvm/lib/Target/X86/X86AsmPrinter.h
index 1bbfa55..b2fbe05 100755
--- a/llvm/lib/Target/X86/X86AsmPrinter.h
+++ b/llvm/lib/Target/X86/X86AsmPrinter.h
@@ -67,7 +67,7 @@
 
   void getAnalysisUsage(AnalysisUsage &AU) const {
     AU.setPreservesAll();
-    if (Subtarget->isTargetDarwin()) {
+    if (Subtarget->isTargetDarwin() || Subtarget->isTargetELF()) {
       AU.addRequired<MachineDebugInfo>();
     }
     MachineFunctionPass::getAnalysisUsage(AU);