perl-XML-DifferenceMarkup-1.05-33.fc40 fails to build in Fedora 40:

g++ -c  -I/usr/include/libxml2 -I/usr/include/diffmark -I. -D_REENTRANT -D_GNU_SOURCE -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Wno-complain-wrong-lang -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -fwrapv -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Wno-complain-wrong-lang -Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64   -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer   -DVERSION=\"1.05\" -DXS_VERSION=\"1.05\" -fPIC "-I/usr/lib64/perl5/CORE"  -DHAVE_UTF8 perl-libxml-sax.c
perl-libxml-sax.c: In function ‘int PmmSaxError(void*, const char*, ...)’:
perl-libxml-sax.c:1411:47: error: invalid conversion from ‘const xmlError*’ {aka ‘const _xmlError*’} to ‘xmlErrorPtr’ {aka ‘_xmlError*’} [-fpermissive]
 1411 |     xmlErrorPtr last_err = xmlCtxtGetLastError( ctxt );
      |                            ~~~~~~~~~~~~~~~~~~~^~~~~~~~
      |                                               |
      |                                               const xmlError* {aka const _xmlError*}

A difference between passing and failing build roots is at <https://koschei.fedoraproject.org/build/16722996>. This failure is probably triggered by upgrading libxml2-devel from 2.11.5-1.fc40 to 2.12.0-1.fc40.