Remove pipe flag from GCC

As found by @tclune and @gmao-ckung, XCode 16 on macOS has caused an issue where the -pipe GNU compiler flag causes errors in CMake builds.

It doesn't seem to be crucial and research online says the pipe flag isn't really that crucial for fast builds anymore.

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What's Changed

• Remove pipe from GNU flags by @mathomp4 in #8

Full Changelog: geos/v1.2.0...geos/v1.4.0