unclear when valgrind headers changed

git-svn-id: https://svn.r-project.org/R/trunk@66966 00db46b3-68df-0310-9c12-caf00c1e9a41
probably safer test

git-svn-id: https://svn.r-project.org/R/trunk@66967 00db46b3-68df-0310-9c12-caf00c1e9a41