Log Message:
Update afl to 2.06b:

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Version 2.06b:
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  - Worked around LLVM persistent mode hiccups with -shared code.
    Contributed by Christian Holler.

  - Added __AFL_COMPILER as a convenient way to detect that something is
    built under afl-gcc / afl-clang / afl-clang-fast and enable custom
    optimizations in your code. Suggested by Pedro Corte-Real.

  - Upstreamed several minor changes developed by Franjo Ivancic to
    allow AFL to be built as a library. This is fairly use-specific and
    may have relatively little appeal to general audiences.