configure: Use -Werror to check for existence of -no-pie

Clang throws a warning instead of an error when it is passed -no-pie,

    clang: warning: argument unused during compilation: '-nopie'
    [-Wunused-command-line-argument]

Consequently configure concludes that it supports -no-pie. However, this
will fail when used with -Werror. The solution is to simply use -Werror
in the configure check.

Thanks to @goldfire for reporting this.

Reviewers: hvr

Subscribers: thomie, carter, goldfire

Differential Revision: https://phabricator.haskell.org/D4557