If executing a file fails with an [ENOEXEC] error, the shell executes the
file as a shell script, except that this execution may instead result in an
error message if the file is binary.
Per a recent Austin Group interpretation, we will need to change this to
allow a concatenation of a shell script and a binary payload. See
Austin Group bugs #1226 and #1250.
MFC after: 1 week
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