Configure's -no-pie check is fragile under newer clang versions

Modern clang versions are quite picky when it comes to reporting redundant arguments. In particular, they will warn when -no-pie is passed when no linking is necessary.

Previously the configure script used a $CC -Werror -no-pie -E /dev/null invocation to test whether -no-pie is necessary. Unfortunately, this means that clang will throw a redundant argument warning, causing configure to conclude that -no-pie was not supported. To be robust, the check needs to test a command-line that requires linking.