argument: Fix cppcoreguidelines-avoid-non-const-global-variables
```
../argument.hpp:52:31: error: variable 'optionstr' is non-const and globally accessible, consider making it const [cppcoreguidelines-avoid-non-const-global-variables,-warnings-as-errors]
static inline const char* optionstr = "p:?h";
^
```
Change-Id: I2c22a9f2c5cd9dbe0ce23928663dd10679f873c4
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/argument.hpp b/argument.hpp
index 3dd2b9e..6afb762 100644
--- a/argument.hpp
+++ b/argument.hpp
@@ -49,7 +49,7 @@
};
/** @brief optstring as needed by getopt_long */
- static inline const char* optionstr = "p:?h";
+ static inline const char* const optionstr = "p:?h";
};
} // namespace led