Disable GCC warnings/errors about wrong self casts in final function calls

Numerous packages fail to build due to -Werror=incompatible-pointer-types
being the default in Fedora 40+.

The code is generated by Cython. No known fix at this time,
so better to disable the warning here than in each individual package.

6039.patch

@@ -0,0 +1,64 @@
+From 2b1022efeeeefe1b813bb0810675a6fcb98cbb6e Mon Sep 17 00:00:00 2001
+From: Stefan Behnel <stefan_ml@behnel.de>
+Date: Wed, 28 Feb 2024 10:03:58 +0100
+Subject: [PATCH 1/2] Disable GCC warnings/errors about wrong self casts in
+ final function calls.
+
+See https://github.com/cython/cython/issues/2747
+---
+ Cython/Compiler/ExprNodes.py | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/Cython/Compiler/ExprNodes.py b/Cython/Compiler/ExprNodes.py
+index d46e8b0cbdd..62364edd1b1 100644
+--- a/Cython/Compiler/ExprNodes.py
++++ b/Cython/Compiler/ExprNodes.py
+@@ -6498,7 +6498,13 @@ def generate_result_code(self, code):
+                         goto_error = code.error_goto_if(" && ".join(exc_checks), self.pos)
+                     else:
+                         goto_error = ""
++                    if self.function.is_attribute and self.function.entry and self.function.entry.final_func_cname:
++                        # Hack around https://github.com/cython/cython/issues/2747
++                        # Disable GCC warnings/errors for wrong self casts.
++                        code.putln('#pragma GCC diagnostic ignored "-Wincompatible-pointer-types"')
+                     code.putln("%s%s; %s" % (lhs, rhs, goto_error))
++                    if self.function.is_attribute and self.function.entry and self.function.entry.final_func_cname:
++                        code.putln("#pragma GCC diagnostic pop")
+                 if self.type.is_pyobject and self.result():
+                     self.generate_gotref(code)
+             if self.has_optional_args:
+
+From facecc5fe67feac147afa47008a06f766bfb8cd3 Mon Sep 17 00:00:00 2001
+From: Stefan Behnel <stefan_ml@behnel.de>
+Date: Sat, 2 Mar 2024 08:54:26 +0100
+Subject: [PATCH 2/2] Do not generate pragma in C++ mode since it is only valid
+ for gcc, not gpp.
+
+---
+ Cython/Compiler/ExprNodes.py | 9 +++++++--
+ 1 file changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/Cython/Compiler/ExprNodes.py b/Cython/Compiler/ExprNodes.py
+index 62364edd1b1..7ee239ae579 100644
+--- a/Cython/Compiler/ExprNodes.py
++++ b/Cython/Compiler/ExprNodes.py
+@@ -6498,12 +6498,17 @@ def generate_result_code(self, code):
+                         goto_error = code.error_goto_if(" && ".join(exc_checks), self.pos)
+                     else:
+                         goto_error = ""
+-                    if self.function.is_attribute and self.function.entry and self.function.entry.final_func_cname:
++                    undo_gh2747_hack = False
++                    if (self.function.is_attribute and
++                            self.function.entry and self.function.entry.final_func_cname and
++                            not code.funcstate.scope.is_cpp()
++                            ):
+                         # Hack around https://github.com/cython/cython/issues/2747
+                         # Disable GCC warnings/errors for wrong self casts.
+                         code.putln('#pragma GCC diagnostic ignored "-Wincompatible-pointer-types"')
++                        undo_gh2747_hack = True
+                     code.putln("%s%s; %s" % (lhs, rhs, goto_error))
+-                    if self.function.is_attribute and self.function.entry and self.function.entry.final_func_cname:
++                    if undo_gh2747_hack:
+                         code.putln("#pragma GCC diagnostic pop")
+                 if self.type.is_pyobject and self.result():
+                     self.generate_gotref(code)

Cython.spec

@@ -16,6 +16,10 @@ Source:         https://github.com/cython/cython/archive/%{version}/Cython-%{ver
 # Use Python 3.13.0a4 PyCFunctionFastWithKeywords
 Patch:          https://github.com/cython/cython/pull/6003.patch
 
+# Disable GCC warnings/errors about wrong self casts in final function calls
+# Upstream issue: https://github.com/cython/cython/issues/2747
+Patch:          https://github.com/cython/cython/pull/6039.patch
+
 BuildRequires:  python3-devel
 
 %if %{with tests}