Fix a comment in the code

The -ldl library is missing on NetBSD too, make the comment more generic.

llvm-svn: 320165
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 5e7fe43..206ee54 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -544,7 +544,7 @@
     CmdArgs.push_back("-lrt");
   }
   CmdArgs.push_back("-lm");
-  // There's no libdl on FreeBSD or RTEMS.
+  // There's no libdl on all OSes.
   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD &&
       TC.getTriple().getOS() != llvm::Triple::NetBSD &&
       TC.getTriple().getOS() != llvm::Triple::RTEMS)