super-slicer: fix build (#298652)

cgal bump in #292492 broke the build

pkgs/applications/misc/prusa-slicer/meshboolean-const.patch

@@ -0,0 +1,19 @@
+diff --git a/src/libslic3r/MeshBoolean.cpp b/src/libslic3r/MeshBoolean.cpp
+index 31fdc35..32acbf8 100644
+--- a/src/libslic3r/MeshBoolean.cpp
++++ b/src/libslic3r/MeshBoolean.cpp
+@@ -147,12 +147,12 @@ template<class _Mesh> TriangleMesh cgal_to_triangle_mesh(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;

pkgs/applications/misc/prusa-slicer/super-slicer.nix

@@ -16,6 +16,7 @@ let
       ];
       sha256 = "sha256-v0q2MhySayij7+qBTE5q01IOq/DyUcWnjpbzB/AV34c=";
     })
+    ./meshboolean-const.patch
   ];
 
   versions = {