Added patch to allow bash command substitutions, disabled by default.
Previously, if command arguments were enabled, NRPE would allow arguments
of the form $(...), which would cause a bash command substitution and could
be used for malicious intent. This patch adds both a configure-time option,
--enable-bash-command-substitution, and a configuration file option,
allow_bash_command_substitution. Both of these, along with the
--enable-command-args configure-time option and the dont_blame_nrpe
configuration file option must be enabled or arguments containing $(
will be rejected.
In addition, some clean-up of the configure.in script was done so options
display nicely when the --help argument is specified to the configure script.