libxml2: update to 2.12.1.

[triallax]

Testing the changes

• I tested the changes in this PR: YES

[leahneukirchen]

musl tests were broken before.

[classabbyamp]

reverted: 343da92

breaks inkscape build:

../src/object/uri.cpp: In constructor 'Inkscape::URI::URI(const gchar*, const char*)':
../src/object/uri.cpp:86:9: error: 'xmlFree' was not declared in this scope; did you mean 'xmlFreeURI'?
   86 |         xmlFree(full);
      |         ^~~~~~~
      |         xmlFreeURI
../src/object/uri.cpp:89:9: error: 'xmlFree' was not declared in this scope; did you mean 'xmlFreeURI'?
   89 |         xmlFree(escaped);
      |         ^~~~~~~
      |         xmlFreeURI
../src/object/uri.cpp: In member function 'std::string Inkscape::URI::str(const char*) const':
../src/object/uri.cpp:292:9: error: 'xmlFree' was not declared in this scope; did you mean 'xmlFreeURI'?
  292 |         xmlFree(saveuri);
      |         ^~~~~~~
      |         xmlFreeURI

[triallax]

Oops, I'll take a look at it later

[leahneukirchen]

Fix for inkscape:

--- a/src/object/uri.h
+++ b/src/object/uri.h
@@ -13,6 +13,7 @@
 #define INKSCAPE_URI_H
 
 #include <libxml/uri.h>
+#include <libxml/xmlmemory.h>
 #include <memory>
 #include <string>
 

[leahneukirchen]

s3fs-fuse has similar issues, and needs <libxml/xmlmemory.h> and <libxml/parser.h>.

[triallax]

I did some mass builds, the bump breaks at least dozens of packages in a similar way. :/