pip3 install lxml reports
```
Collecting lxml
Using cached lxml-4.9.3.tar.gz (3.6 MB)
Preparing metadata (setup.py) ... done
Building wheels for collected packages: lxml
Building wheel for lxml (setup.py) ... error
error: subprocess-exited-with-error
× python setup.py bdist_wheel did not run successfully.
│ exit code: 1
╰─> [174 lines of output]
Building lxml version 4.9.3.
/data/data/com.termux/files/usr/tmp/pip-install-dns92bfc/lxml_8be6a95f795443dcb76ce90a34da4f2c/setup.py:67: DeprecationWarning: pkg_resources is deprecated as an API. See https://setuptools.pypa.io/en/latest/pkg_resources.html
import pkg_resources
Building without Cython.
Building against libxml2 2.12.1 and libxslt 1.1.39
Building against libxml2/libxslt in the following directory: /data/data/com.termux/files/usr/lib
running bdist_wheel
running build
running build_py
creating build
creating build/lib.linux-aarch64-cpython-311
creating build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/ElementInclude.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/__init__.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/_elementpath.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/builder.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/cssselect.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/doctestcompare.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/pyclasslookup.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/sax.py -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/usedoctest.py -> build/lib.linux-aarch64-cpython-311/lxml
creating build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/__init__.py -> build/lib.linux-aarch64-cpython-311/lxml/includes
creating build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/ElementSoup.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/__init__.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/_diffcommand.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/_html5builder.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/_setmixin.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/builder.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/clean.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/defs.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/diff.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/formfill.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/html5parser.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/soupparser.py -> build/lib.linux-aarch64-cpython-311/lxml/html
copying src/lxml/html/usedoctest.py -> build/lib.linux-aarch64-cpython-311/lxml/html
creating build/lib.linux-aarch64-cpython-311/lxml/isoschematron
copying src/lxml/isoschematron/__init__.py -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron
copying src/lxml/etree.h -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/etree_api.h -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/lxml.etree.h -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/lxml.etree_api.h -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/etree.pyx -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/objectify.pyx -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/apihelpers.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/classlookup.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/cleanup.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/debug.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/docloader.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/dtd.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/extensions.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/iterparse.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/nsclasses.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/objectpath.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/parser.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/parsertarget.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/proxy.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/public-api.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/readonlytree.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/relaxng.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/saxparser.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/schematron.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/serializer.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/xinclude.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/xmlerror.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/xmlid.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/xmlschema.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/xpath.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/xslt.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/xsltext.pxi -> build/lib.linux-aarch64-cpython-311/lxml
copying src/lxml/includes/__init__.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/c14n.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/config.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/dtdvalid.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/etreepublic.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/htmlparser.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/relaxng.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/schematron.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/tree.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/uri.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/xinclude.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/xmlerror.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/xmlparser.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/xmlschema.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/xpath.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/xslt.pxd -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/etree_defs.h -> build/lib.linux-aarch64-cpython-311/lxml/includes
copying src/lxml/includes/lxml-version.h -> build/lib.linux-aarch64-cpython-311/lxml/includes
creating build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources
creating build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/rng
copying src/lxml/isoschematron/resources/rng/iso-schematron.rng -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/rng
creating build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl
copying src/lxml/isoschematron/resources/xsl/RNG2Schtrn.xsl -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl
copying src/lxml/isoschematron/resources/xsl/XSD2Schtrn.xsl -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl
creating build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_abstract_expand.xsl -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_dsdl_include.xsl -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_schematron_message.xsl -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_schematron_skeleton_for_xslt1.xsl -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/iso_svrl_for_xslt1.xsl -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
copying src/lxml/isoschematron/resources/xsl/iso-schematron-xslt1/readme.txt -> build/lib.linux-aarch64-cpython-311/lxml/isoschematron/resources/xsl/iso-schematron-xslt1
running build_ext
building 'lxml.etree' extension
creating build/temp.linux-aarch64-cpython-311
creating build/temp.linux-aarch64-cpython-311/src
creating build/temp.linux-aarch64-cpython-311/src/lxml
aarch64-linux-android-clang -DNDEBUG -g -fwrapv -O3 -Wall -fstack-protector-strong -O3 -fstack-protector-strong -O3 -fPIC -DCYTHON_CLINE_IN_TRACEBACK=0 -I/data/data/com.termux/files/usr/include/libxml2 -I/data/data/com.termux/files/usr/include -Isrc -Isrc/lxml/includes -I/data/data/com.termux/files/usr/include/python3.11 -c src/lxml/etree.c -o build/temp.linux-aarch64-cpython-311/src/lxml/etree.o -w
src/lxml/etree.c:113152:38: error: incompatible function pointer types assigning to 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') from 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') [-Wincompatible-function-pointer-types]
113152 | __pyx_v_self->_c_ctxt->sax->serror = __pyx_f_4lxml_5etree__receiveParserError;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/lxml/etree.c:117640:25: error: incompatible function pointer types assigning to 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') from 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') [-Wincompatible-function-pointer-types]
117640 | __pyx_v_sax->serror = __pyx_f_4lxml_5etree__receiveParserError;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/lxml/etree.c:181724:28: error: incompatible function pointer types assigning to 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') from 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') [-Wincompatible-function-pointer-types]
181724 | __pyx_v_xpathCtxt->error = __pyx_f_4lxml_5etree__receiveXPathError;
| ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
src/lxml/etree.c:218998:60: error: incompatible function pointer types passing 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') to parameter of type 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') [-Wincompatible-function-pointer-types]
218998 | xmlRelaxNGSetParserStructuredErrors(__pyx_v_parser_ctxt, __pyx_f_4lxml_5etree__receiveError, ((void *)__pyx_v_self->__pyx_base._error_log));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/data/com.termux/files/usr/include/libxml2/libxml/relaxng.h:155:30: note: passing argument to parameter 'serror' here
155 | xmlStructuredErrorFunc serror,
| ^
src/lxml/etree.c:219416:60: error: incompatible function pointer types passing 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') to parameter of type 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') [-Wincompatible-function-pointer-types]
219416 | xmlRelaxNGSetValidStructuredErrors(__pyx_v_valid_ctxt, __pyx_f_4lxml_5etree__receiveError, ((void *)__pyx_v_self->__pyx_base._error_log));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/data/com.termux/files/usr/include/libxml2/libxml/relaxng.h:184:31: note: passing argument to parameter 'serror' here
184 | xmlStructuredErrorFunc serror, void *ctx);
| ^
src/lxml/etree.c:220305:59: error: incompatible function pointer types passing 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') to parameter of type 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') [-Wincompatible-function-pointer-types]
220305 | xmlSchemaSetParserStructuredErrors(__pyx_v_parser_ctxt, __pyx_f_4lxml_5etree__receiveError, ((void *)__pyx_v_self->__pyx_base._error_log));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/data/com.termux/files/usr/include/libxml2/libxml/xmlschemas.h:156:30: note: passing argument to parameter 'serror' here
156 | xmlStructuredErrorFunc serror,
| ^
src/lxml/etree.c:220848:59: error: incompatible function pointer types passing 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') to parameter of type 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') [-Wincompatible-function-pointer-types]
220848 | xmlSchemaSetValidStructuredErrors(__pyx_v_valid_ctxt, __pyx_f_4lxml_5etree__receiveError, ((void *)__pyx_v_self->__pyx_base._error_log));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/data/com.termux/files/usr/include/libxml2/libxml/xmlschemas.h:185:30: note: passing argument to parameter 'serror' here
185 | xmlStructuredErrorFunc serror,
| ^
src/lxml/etree.c:221613:66: error: incompatible function pointer types passing 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') to parameter of type 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') [-Wincompatible-function-pointer-types]
221613 | xmlSchemaSetValidStructuredErrors(__pyx_v_self->_valid_ctxt, __pyx_f_4lxml_5etree__receiveError, ((void *)__pyx_v_error_log));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/data/com.termux/files/usr/include/libxml2/libxml/xmlschemas.h:185:30: note: passing argument to parameter 'serror' here
185 | xmlStructuredErrorFunc serror,
| ^
src/lxml/etree.c:222790:63: error: incompatible function pointer types passing 'void (void *, xmlError *)' (aka 'void (void *, struct _xmlError *)') to parameter of type 'xmlStructuredErrorFunc' (aka 'void (*)(void *, const struct _xmlError *)') [-Wincompatible-function-pointer-types]
222790 | xmlSchematronSetValidStructuredErrors(__pyx_v_valid_ctxt, __pyx_f_4lxml_5etree__receiveError, ((void *)__pyx_v_self->__pyx_base._error_log));
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/data/data/com.termux/files/usr/include/libxml2/libxml/schematron.h:105:31: note: passing argument to parameter 'serror' here
105 | xmlStructuredErrorFunc serror,
| ^
9 errors generated.
Compile failed: command '/data/data/com.termux/files/usr/bin/aarch64-linux-android-clang' failed with exit code 1
creating data
creating data/data
creating data/data/com.termux
creating data/data/com.termux/files
creating data/data/com.termux/files/usr
creating data/data/com.termux/files/usr/tmp
cc -I/data/data/com.termux/files/usr/include/libxml2 -I/data/data/com.termux/files/usr/include -I/usr/include/libxml2 -c /data/data/com.termux/files/usr/tmp/xmlXPathInitd09ks7k3.c -o data/data/com.termux/files/usr/tmp/xmlXPathInitd09ks7k3.o
/data/data/com.termux/files/usr/tmp/xmlXPathInitd09ks7k3.c:3:5: warning: 'xmlXPathInit' is deprecated [-Wdeprecated-declarations]
3 | xmlXPathInit();
| ^
/data/data/com.termux/files/usr/include/libxml2/libxml/xpath.h:562:1: note: 'xmlXPathInit' has been explicitly marked deprecated here
562 | XML_DEPRECATED
| ^
/data/data/com.termux/files/usr/include/libxml2/libxml/xmlversion.h:447:43: note: expanded from macro 'XML_DEPRECATED'
447 | # define XML_DEPRECATED __attribute__((deprecated))
| ^
1 warning generated.
cc data/data/com.termux/files/usr/tmp/xmlXPathInitd09ks7k3.o -L/data/data/com.termux/files/usr/lib -lxml2 -o a.out
error: command '/data/data/com.termux/files/usr/bin/aarch64-linux-android-clang' failed with exit code 1
[end of output]
note: This error originates from a subprocess, and is likely not a problem with pip.
ERROR: Failed building wheel for lxml
Running setup.py clean for lxml
Failed to build lxml
ERROR: Could not build wheels for lxml, which is required to install pyproject.toml-based projects
```
Thanks for the report. That is annoying, looks like they constified their API a bit more, leading to backward incompatibilities.
The problem is that adapting the code on lxml side would mean that you get the same error/warning with older libxml2 versions, so there is no clean way out. Changing the code to use 'const' might at least turn the error into a warning. We'll see. Maybe an explicit cast might help hiding it, although that always bares the risk of undetected future problems. Annoying, as I wrote…