anti-patterns: use cli11 instead of custom parser
Many OpenBMC applications have a custom ArgumentParser object to provide
a modern argument parsing interface. These are nearly identical between
daemons. The CLI11 library provides a modern argument parsing interface
with advanced validation.
Change-Id: I11ca97b2990e342c203ec54b9f3d40bbcebb55eb
Signed-off-by: Patrick Venture <venture@google.com>
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+## Custom ArgumentParser object
+
+### Identification
+
+The ArgumentParser object is typically present to wrap calls to get options.
+It abstracts away the parsing and provides a `[]` operator to access the
+parameters.
+
+### Description
+
+Writing a custom ArgumentParser object creates nearly duplicate code in a
+repository. The ArgumentParser itself is the same, however, the options
+provided differ. Writing a custom argument parser re-invents the wheel on
+c++ command line argument parsing.
+
+### Background
+
+The ArgumentParser exists because it was in place early and then copied into
+each new repository as an easy way to handle argument parsing.
+
+### Resolution
+
+The CLI11 library was designed and implemented specifically to support modern
+argument parsing. It handles the cases seen in OpenBMC daemons and has some
+handy built-in validators, and allows easy customizations to validation.
+
## Explicit AC_MSG_ERROR on PKG_CHECK_MODULES failure
### Identification