MariaDB 11.4.5 fails to build from source when compiling against libxml2 2.14.0.

The proximate error is in the attached file error.txt.

The root cause is that plgxml.h makes an #ifdef check against an undocumented typedef:

#if !defined(BASE_BUFFER_SIZE)

to detect whether libxml2's tree.h was included, but in this recent commit, the definition of BASE_BUFFER_SIZE was removed from tree.h:

https://github.com/GNOME/libxml2/commit/696572248fe96c44a60120be5b3ba42a4abcfb31#diff-4d724327c74c8e7b349eb38258524a6228cc3e06b5d10f783557a8f38bcf737bL67

Replacing BASE_BUFFER_SIZE with

__XML_TREE_H__

in plgxml.h fixes the problem.