bambu-studio: Fix build

It was broken by a cgal bump in https://github.com/NixOS/nixpkgs/pull/292492

pkgs/applications/misc/bambu-studio/default.nix

@@ -113,6 +113,8 @@ stdenv.mkDerivation rec {
   patches = [
     # Fix for webkitgtk linking
     ./0001-not-for-upstream-CMakeLists-Link-against-webkit2gtk-.patch
+    # Fix build with cgal-5.6.1+
+    ./meshboolean-const.patch
   ];
 
   doCheck = true;

pkgs/applications/misc/bambu-studio/meshboolean-const.patch

@@ -0,0 +1,21 @@
+Fix build with cgal 5.6.1+
+
+diff --git a/src/libslic3r/MeshBoolean.cpp b/src/libslic3r/MeshBoolean.cpp
+index 50bbc099..b05245d3 100644
+--- a/src/libslic3r/MeshBoolean.cpp
++++ b/src/libslic3r/MeshBoolean.cpp
+@@ -200,12 +200,12 @@ indexed_triangle_set cgal_to_indexed_triangle_set(const _Mesh &cgalmesh)
+     const auto &vertices = cgalmesh.vertices();
+     int vsize = int(vertices.size());
+
+-    for (auto &vi : vertices) {
++    for (const auto &vi : vertices) {
+         auto &v = cgalmesh.point(vi); // Don't ask...
+         its.vertices.emplace_back(to_vec3f(v));
+     }
+
+-    for (auto &face : faces) {
++    for (const auto &face : faces) {
+         auto vtc = cgalmesh.vertices_around_face(cgalmesh.halfedge(face));
+
+         int i = 0;