Compiling with libxml in MacOS Catalina

The problem When compiling Emacs 28.05, make bootstrap failed with fatal error: 'libxml/tree.h' file not found while and configure were successfully executed. Troubleshooting The error message pointed out the culprit, libxml.

Lost in reference

I have an evergrowing pile of unread but interesting paper in my download folder. With the size growing from several hundred MB to more than 2 GB, it is becoming hard to find a pdf file when I really need it.