configure: fix detection of atomic builtins in libatomic configure script
Alpine's --enable-autolink-libatomic (which is enabled for riscv64 by default) causes the libatomic configure script to incorrectly detect which builtins are available on riscv64. This then causes incorrect code generation for libatomic since it assumes compiler builtins to be available which are not actually available on riscv64.
This commit fixes this issue by disabling linking of libatomic configure test code entirely, thereby preventing linking against libatomic.
See: