Use AT_PAGESZ for sysconf(_SC_PAGE_SIZE).

Bug: http://b/18342333
Change-Id: Id12ed4e85a0f35d7d27202f7792df42a65a74b4e
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 79c16d7..b29c6f3 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -694,6 +694,8 @@
   VERIFY_SYSCONF_POSITIVE(_SC_IOV_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_PAGESIZE);
   VERIFY_SYSCONF_POSITIVE(_SC_PAGE_SIZE);
+  VerifySysconf(_SC_PAGE_SIZE, "_SC_PAGE_SIZE",
+                [](long v){return v == sysconf(_SC_PAGESIZE) && v == getpagesize();});
   VERIFY_SYSCONF_POSITIVE(_SC_XOPEN_UNIX);
   VERIFY_SYSCONF_POSITIVE(_SC_AIO_LISTIO_MAX);
   VERIFY_SYSCONF_POSITIVE(_SC_AIO_MAX);