File root6-minuit2-rspan-missing.patch of Package root6

From dad014d6f3d266511d7a46973632d4edc7f8838f Mon Sep 17 00:00:00 2001
From: Jonas Rembser <jonas.rembser@cern.ch>
Date: Thu, 12 Jun 2025 14:02:05 +0200
Subject: [PATCH] [Minuit2] Correctly copy ROOT's `std::span` headers for
 standalone build

Correctly copy ROOT's `std::span` headers to setup the Minuit2
standalone build.

Now the treatment of the `std::span` headers follows the same approach
that is already taken for other headers that are copied from ROOT Math:

See https://github.com/root-project/root/blob/master/math/minuit2/src/math/CMakeLists.txt#L36
See https://github.com/root-project/root/blob/master/math/minuit2/src/math/CMakeLists.txt#L97

Closes #18974.
---
 math/minuit2/StandAlone.cmake |    8 ++++++++
 1 file changed, 8 insertions(+)

Index: root-6.32.20/math/minuit2/StandAlone.cmake
===================================================================
--- root-6.32.20.orig/math/minuit2/StandAlone.cmake
+++ root-6.32.20/math/minuit2/StandAlone.cmake
@@ -39,6 +39,14 @@ endfunction()
 # This file adds copy_standalone
 include(copy_standalone.cmake)
 
+# We need the std::span backport. This can be removed once the minimum C++
+# standard gets raised to C++20, which should happen if also the minimum C++
+# standard of ROOT gets raised and the std::span backport in RSpan is removed.
+set(SPAN_HEADERS RSpan.hxx span.hxx)
+copy_standalone(SOURCE ../../core/foundation/inc/ROOT DESTINATION inc/ROOT OUTPUT SPAN_HEADERS
+                FILES ${SPAN_HEADERS})
+install(FILES ${SPAN_HEADERS} DESTINATION include/Minuit2/ROOT)
+
 # Copy these files in if needed
 copy_standalone(SOURCE ../../core/foundation/inc/ROOT DESTINATION . OUTPUT VERSION_FILE
                 FILES RVersion.hxx)