Function release_c_flags 

pub fn release_c_flags(
    arch: &str,
    vendor: &str,
    target: CpuTarget,
    march: Option<&str>,
) -> String

CMAKE_C_FLAGS_RELEASE for the Aeron C build of arch (CARGO_CFG_TARGET_ARCH) and vendor (CARGO_CFG_TARGET_VENDOR) for target. march (RUSTERON_C_MARCH) overrides the target’s -march.