As reported by Matthias Klose in Debian Bug #1106621:

http://qa-logs.debian.net/2025/05/23/spatialite_5.1.0-3_unstable_libxml2.log

[...]
wfs_in.c: In function 'reset_wfs_http_connection':
wfs_in.c:4640:5: error: implicit declaration of function 
'xmlNanoHTTPCleanup' [-Wimplicit-function-declaration]
 4640 |     xmlNanoHTTPCleanup ();
      |     ^~~~~~~~~~~~~~~~~~
wfs_in.c: In function 'reset_wfs_http_connection':
wfs_in.c:4640:5: error: implicit declaration of function 
'xmlNanoHTTPCleanup' [-Wimplicit-function-declaration]
 4640 |     xmlNanoHTTPCleanup ();
      |     ^~~~~~~~~~~~~~~~~~
make[4]: *** [Makefile:418: wfs_in.lo] Error 1
make[4]: *** Waiting for unfinished jobs....
make[4]: *** [Makefile:425: wfs_la-wfs_in.lo] Error 1

Update from Mattias Klose in the Debian bugreport:

from libxml2 NEWS:

Support for HTTP and LZMA compression is planned to be removed in the 2.15 release.

I have now uploaded libxml2 with these two features explicitly enabled. But better prepare for 2.15 ...