Here is the error:
* Dependencies could not be completely resolved due to
* the following required packages not being installed:
*
* ~dev-qt/qtxml-5.12.1 pulled in by:
* dev-qt/linguist-tools-5.12.1
*
* ~dev-qt/qtcore-5.12.1 pulled in by:
* dev-qt/linguist-tools-5.12.1
Fix is to manually update linguist-tools:
emerge --oneshot -av linguist-tools