Only link the tests against -ldl on linux

git-svn-id: https://llvm.org/svn/llvm-project/libcxxabi/trunk@220509 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/lit.cfg b/test/lit.cfg
index 87226e9..c2f2e33 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -227,7 +227,7 @@
 if san is None:
     san = getattr(config, 'llvm_use_sanitizer', None)
 if san:
-    if not sys.platform.startswith('freebsd'):
+    if sys.platform == 'linux2':
         link_flags += ['-ldl']
     if san == 'Address':
         compile_flags += ['-fsanitize=address']