Enable LLVM asan support for NetBSD/amd64

Summary:
Enable LLVM asan sanitizer for NetBSD/amd64.

Don't generate -ldl for dlopen(3)-like functions on NetBSD.
These features are available in libc on NetBSD.

Sponsored by <The NetBSD Foundation>

Reviewers: joerg, eugenis, kcc, dim

Reviewed By: dim

Subscribers: #clang, #sanitizers

Tags: #clang, #sanitizers

Differential Revision: https://reviews.llvm.org/D34960

llvm-svn: 307104
diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index e8bb703..00bd60b 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -524,6 +524,7 @@
   CmdArgs.push_back("-lm");
   // There's no libdl on FreeBSD or RTEMS.
   if (TC.getTriple().getOS() != llvm::Triple::FreeBSD &&
+      TC.getTriple().getOS() != llvm::Triple::NetBSD &&
       TC.getTriple().getOS() != llvm::Triple::RTEMS)
     CmdArgs.push_back("-ldl");
 }