And also adjust makefiles to remove cases for LLVM 9/10
now as 11 is the current requirement.

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

Need to check that this works OK -- e334bb3
enabled this logic and said "Otherwise if the PrgEnv module isn't loaded,
problems finding libstdc++."

If we can't use the dylib on Crays then we will need to put back in the
static library link strings for the clang libraries.

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

Removes
    util/config/gather-cray-prgenv-arguments.bash
    util/config/gather-pe-chapel-pkgconfig-libs.bash

and makes adjustments to Makefiles and chplenv scripts to allow that.

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

I haven't seen a problem with it yet but I don't want to get in to
changing it in this PR.

See PR chapel-lang#3531 and PR chapel-lang#11615 for some history in this area.

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

Only does something with e.g. make CHPL_LLVM_DYNAMIC=0

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

to address failures with gasnet-mpi configurations

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>

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Signed-off-by: Michael Ferguson <mppf@users.noreply.github.com>