Fix build issue with libxml2 2.14+.

[sugi]

Hello,

I found a build issue with libxml2 2.14 above.

Summary

extconf.rb uses xmlXPtrNewRange as a probe function to detect the presence of libxml2. This function was removed in libxml2 2.14.0 (March 2025) as part of the XPointer range/point extension cleanup, causing the library detection to fail and the gem build to abort with:

checking for xmlXPtrNewRange() in -lxml2... no
checking for xmlXPtrNewRange() in -llibxml2... no
checking for xmlXPtrNewRange() in -lxml2... no
*** extconf failure: Cannot find libxml2.

This affects all systems with libxml2 >= 2.14.0, including Debian forky (testing, which ships libxml2 2.15.x).

Fix

Replace the probe function with xmlXPtrNewContext, which remains in libxml2's XPointer API. The function is not used in the gem's C source code itself — it is only referenced in extconf.rb for library detection.

References

• libxml2 2.14.0 release notes: https://gitlab.gnome.org/GNOME/libxml2/-/releases/v2.14.0
• libxml2 XPointer API (current): https://gnome.pages.gitlab.gnome.org/libxml2/devhelp/libxml2-xpointer.html

[cfis]

Thanks!