There's a merged pull request on the void-packages repository mcpp: fix set_encoding() to understand C.UTF-8 https://github.com/void-linux/void-packages/pull/18288 Description: Function ```set_encoding()``` finds the encoding name by splitting a locale of the form ```en_US.UTF-8``` at the period, but only if the leading part is exactly 5 characters long. ``` $ LC_ALL=C.UTF-8 mcpp /dev/null /dev/null:0: warning: Unknown encoding: C.UTF-8 #line 1 "/dev/null" ``` This patch changes the behaviour to split at the first period instead. This will also fix a warning in ```xrdb```: ``` $ LC_ALL=C.UTF-8 xrdb -merge /dev/null /dev/null:0: warning: Unknown encoding: C.UTF-8 ```