[libcxx] Fixing the Linux sanitizer builds

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@256591 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/libcxx/test/target_info.py b/test/libcxx/test/target_info.py
index c3cefb3..927d7c5 100644
--- a/test/libcxx/test/target_info.py
+++ b/test/libcxx/test/target_info.py
@@ -142,7 +142,8 @@
             flags += ['-lunwind', '-ldl']
         else:
             flags += ['-lgcc_s', '-lgcc']
-        if self.full_config.get_lit_bool('use_sanitizer', False):
+        san = self.get_lit_conf('use_sanitizer', '').strip()
+        if san:
             # The libraries and their order are taken from the
             # linkSanitizerRuntimeDeps function in
             # clang/lib/Driver/Tools.cpp