kahip: Add patch to fix missing include (#46084)

var/spack/repos/builtin/packages/kahip/cstdint.patch

@@ -0,0 +1,11 @@
+diff -Naur spack-src/lib/io/mmap_graph_io.h spack-src/lib/io/mmap_graph_io.patched.h
+--- spack-src/lib/io/mmap_graph_io.h	2024-08-22 17:56:05.689983013 +0200
++++ spack-src/lib/io/mmap_graph_io.patched.h	2024-08-22 17:58:10.915413214 +0200
+@@ -1,6 +1,7 @@
+ #pragma once
+ 
+ #include <cctype>
++#include <cstdint>
+ #include <cstring>
+ #include <fcntl.h>
+ #include <fstream>

var/spack/repos/builtin/packages/kahip/package.py

@@ -69,6 +69,8 @@ class Kahip(CMakePackage):
     patch("fix-sconstruct-for-py3.patch", when="@2:2.10 ^python@3:")
     patch("fix-sconstruct-for-py3-v2.00.patch", when="@2.00 ^python@3:")
 
+    patch("cstdint.patch", when="@3:")
+
     # 'when' decorators to override new CMake build approach (old build was SConstruct).
     @when("@:2.10")
     def patch(self):