Fix warning on gcc 4.3.

"system() declared with attribute warn_unused_result."

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64574 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Unix/Path.inc b/lib/System/Unix/Path.inc
index 8efa2e0..a8dcedb 100644
--- a/lib/System/Unix/Path.inc
+++ b/lib/System/Unix/Path.inc
@@ -658,7 +658,10 @@
   if (remove_contents) {
     // Recursively descend the directory to remove its contents.
     std::string cmd = "/bin/rm -rf " + path;
-    system(cmd.c_str());
+    if (system(cmd.c_str()) != 0) {
+      MakeErrMsg(ErrStr, path + ": failed to recursively remove directory.");
+      return true;
+    }
     return false;
   }