zlib: Enable PIE for native builds

zlib: Enable PIE for native builds

The zlib crate in rust uses libz.a which comes from the zlib-native build.
Some distros like alma9, fedora etc. do not have PIE enabled by default for system compiler.

This leads to target-rust-ccld linking error for cargo-native as (line no 22936):
error: linking with `/home/pokybuild/yocto-worker/qemuarm64/build/build/tmp/work/x86_64-linux/cargo-native/1.79.0/wrapper/target-rust-ccld` failed: exit status: 1

https://autobuilder.yoctoproject.org/typhoon/#/builders/42/builds/9385/steps/13/logs/stdio

Hence, enable PIE option to CFLAGS for native builds.

Signed-off-by: Yash Shinde <Yash.Shinde@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>