we could create a mini project to build a shared library, and use
try_compile() to test if the found gperftools is compiled with -fPIC.
but as we are targeting mostly xenial when enabling
WITH_STATIC_LIBSTDCXX, and google-perftools on xenial by default
is built without -fPIC. so let's keep it simple.
Signed-off-by: Kefu Chai <kchai@redhat.com>
