Fix compiling coroutines with aarch64's branch protection.
    
    Armv8.3+ capable CPUs might segfault with incorrect compilation options.
    See related upstream report: https://bugs.ruby-lang.org/issues/20085
    
    We have hit this on COPR which uses [0] c7g.xlarge AWS flavor for aarch64
    architecture builds. This machine flavor seems to fall into the ARMv8.3+
    range.
    
    Fedora CFLAGS come with `-mbranch-protection=standard` which means that
    both BTI and the PAC protections are used. The option is equivalent
    to `-mbranch-protection=pac-ret+bti`.
    
    However, since the upstream configure.ac automatically appends
    `-mbranch-protection=pac-ret`, the BTI protection is not used
    as the last used option seems to overwrite [1] the Fedora
    default for this.
    
    To resolve both of these issues, of BTI being skipped and the potential
    segfaults a patch is applied.
    
    To fix segfaults an upstream patch was applied [2].
    
    To fix the issue of overridden option I have patched the
    configure.ac file to check for the `=standard` first when searching for a usable
    `-mbranch-protection` option.
    
    The overriding of our options was reported upstream:
    <https://bugs.ruby-lang.org/issues/20154>
    In the same issue I provided the extension of compilation option as an
    attachment, to showcase a workaround that fixes the situation in Fedora.
    
    [0] <https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/Y4GPCGQAZT2LJ5CE7MTIEFKGAPP6O2DW/>
    [1] <https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/QWLEBS4YQH73HJNNLKCCGIIOU3SSXAYK/>
    [2] <https://github.com/ruby/ruby/commit/02973b78f499acc28c714a082c82a846314a911f>