sessiond: avoid std::vector range-ctor on non-standard iterators (libc++)

libc++ SFINAE-gates std::vector(It, It) behind standard iterator requirements.
The events_view/channels_ht_view iterators don’t model Input/Forward, so the
range constructor is not viable and the build fails under clang+libc++.
Populate the vectors via a simple loop instead, which only relies on !=, ++,
and dereference. No functional change; fixes clang/libc++ builds while keeping
libstdc++ behavior unchanged.

Upstream-Status: Submitted [https://review.lttng.org/c/lttng-tools/+/15163]
Signed-off-by: Khem Raj <raj.khem@gmail.com>

Index: lttng-tools-2.14.0/src/bin/lttng-sessiond/ust-registry-channel.cpp
===================================================================
--- lttng-tools-2.14.0.orig/src/bin/lttng-sessiond/ust-registry-channel.cpp
+++ lttng-tools-2.14.0/src/bin/lttng-sessiond/ust-registry-channel.cpp
@@ -529,8 +529,11 @@ void lsu::registry_channel::_accept_on_e
 		events_view(*_events->ht);
 
 	/* Copy the event ptrs from the _events ht to this vector which we'll sort. */
-	std::vector<const lttng::sessiond::ust::registry_event *> sorted_event_classes(
-		events_view.begin(), events_view.end());
+  std::vector<const lttng::sessiond::ust::registry_event *> sorted_event_classes;
+  /* Avoid libc++’s range-ctor SFINAE on non-standard iterators. */
+  for (auto it = events_view.begin(); it != events_view.end(); ++it) {
+  	sorted_event_classes.push_back(*it);
+  }
 
 	std::sort(sorted_event_classes.begin(),
 		  sorted_event_classes.end(),
Index: lttng-tools-2.14.0/src/bin/lttng-sessiond/ust-registry-session.cpp
===================================================================
--- lttng-tools-2.14.0.orig/src/bin/lttng-sessiond/ust-registry-session.cpp
+++ lttng-tools-2.14.0/src/bin/lttng-sessiond/ust-registry-session.cpp
@@ -586,8 +586,11 @@ void lsu::registry_session::_accept_on_s
 						  decltype(lsu::registry_channel::_node),
 						  &lsu::registry_channel::_node>
 		channels_ht_view(*_channels->ht);
-	std::vector<const lttng::sessiond::ust::registry_channel *> sorted_stream_classes(
-		channels_ht_view.begin(), channels_ht_view.end());
+  std::vector<const lttng::sessiond::ust::registry_channel *> sorted_stream_classes;
+  /* Avoid libc++’s range-ctor SFINAE on non-standard iterators. */
+  for (auto it = channels_ht_view.begin(); it != channels_ht_view.end(); ++it) {
+  	sorted_stream_classes.push_back(*it);
+  }
 
 	std::sort(sorted_stream_classes.begin(),
 		  sorted_stream_classes.end(),