gnu: python-libxml2: Fix building with python-3.9.

* gnu/packages/xml.scm (python-libxml2)[source]: Add patch.
* gnu/packages/patches/python-libxml2-python39-compat.patch: New file.
* gnu/local.mk (dist_patch_DATA): Register it.

1 files changed, 94 insertions, 0 deletions

diff --git a/gnu/packages/patches/python-libxml2-python39-compat.patch b/gnu/packages/patches/python-libxml2-python39-compat.patch
new file mode 100644
index 0000000000..a707ea3434
--- /dev/null
+++ b/gnu/packages/patches/python-libxml2-python39-compat.patch
@@ -0,0 +1,94 @@
+https://gitlab.gnome.org/GNOME/libxml2/-/commit/e4fb36841800038c289997432ca547c9bfef9db1.patch
+
+From e4fb36841800038c289997432ca547c9bfef9db1 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Miro=20Hron=C4=8Dok?= <miro@hroncok.cz>
+Date: Fri, 28 Feb 2020 12:48:14 +0100
+Subject: [PATCH] Parenthesize Py<type>_Check() in ifs
+
+In C, if expressions should be parenthesized.
+PyLong_Check, PyUnicode_Check etc. happened to expand to a parenthesized
+expression before, but that's not API to rely on.
+
+Since Python 3.9.0a4 it needs to be parenthesized explicitly.
+
+Fixes https://gitlab.gnome.org/GNOME/libxml2/issues/149
+---
+ python/libxml.c |  4 ++--
+ python/types.c  | 12 ++++++------
+ 2 files changed, 8 insertions(+), 8 deletions(-)
+
+diff --git a/python/libxml.c b/python/libxml.c
+index bc676c4e..81e709f3 100644
+--- a/python/libxml.c
++++ b/python/libxml.c
+@@ -294,7 +294,7 @@ xmlPythonFileReadRaw (void * context, char * buffer, int len) {
+ 	lenread = PyBytes_Size(ret);
+ 	data = PyBytes_AsString(ret);
+ #ifdef PyUnicode_Check
+-    } else if PyUnicode_Check (ret) {
++    } else if (PyUnicode_Check (ret)) {
+ #if PY_VERSION_HEX >= 0x03030000
+         Py_ssize_t size;
+ 	const char *tmp;
+@@ -359,7 +359,7 @@ xmlPythonFileRead (void * context, char * buffer, int len) {
+ 	lenread = PyBytes_Size(ret);
+ 	data = PyBytes_AsString(ret);
+ #ifdef PyUnicode_Check
+-    } else if PyUnicode_Check (ret) {
++    } else if (PyUnicode_Check (ret)) {
+ #if PY_VERSION_HEX >= 0x03030000
+         Py_ssize_t size;
+ 	const char *tmp;
+diff --git a/python/types.c b/python/types.c
+index c2bafeb1..ed284ec7 100644
+--- a/python/types.c
++++ b/python/types.c
+@@ -602,16 +602,16 @@ libxml_xmlXPathObjectPtrConvert(PyObject *obj)
+     if (obj == NULL) {
+         return (NULL);
+     }
+-    if PyFloat_Check (obj) {
++    if (PyFloat_Check (obj)) {
+         ret = xmlXPathNewFloat((double) PyFloat_AS_DOUBLE(obj));
+-    } else if PyLong_Check(obj) {
++    } else if (PyLong_Check(obj)) {
+ #ifdef PyLong_AS_LONG
+         ret = xmlXPathNewFloat((double) PyLong_AS_LONG(obj));
+ #else
+         ret = xmlXPathNewFloat((double) PyInt_AS_LONG(obj));
+ #endif
+ #ifdef PyBool_Check
+-    } else if PyBool_Check (obj) {
++    } else if (PyBool_Check (obj)) {
+ 
+         if (obj == Py_True) {
+           ret = xmlXPathNewBoolean(1);
+@@ -620,14 +620,14 @@ libxml_xmlXPathObjectPtrConvert(PyObject *obj)
+           ret = xmlXPathNewBoolean(0);
+         }
+ #endif
+-    } else if PyBytes_Check (obj) {
++    } else if (PyBytes_Check (obj)) {
+         xmlChar *str;
+ 
+         str = xmlStrndup((const xmlChar *) PyBytes_AS_STRING(obj),
+                          PyBytes_GET_SIZE(obj));
+         ret = xmlXPathWrapString(str);
+ #ifdef PyUnicode_Check
+-    } else if PyUnicode_Check (obj) {
++    } else if (PyUnicode_Check (obj)) {
+ #if PY_VERSION_HEX >= 0x03030000
+         xmlChar *str;
+ 	const char *tmp;
+@@ -650,7 +650,7 @@ libxml_xmlXPathObjectPtrConvert(PyObject *obj)
+ 	ret = xmlXPathWrapString(str);
+ #endif
+ #endif
+-    } else if PyList_Check (obj) {
++    } else if (PyList_Check (obj)) {
+         int i;
+         PyObject *node;
+         xmlNodePtr cur;
+-- 
+GitLab
+