Commit d49c5519f8 for perl

commit d49c5519f82b768164e545f2add6568472d0a8a3
Author: Tony Cook <tony@develop-help.com>
Date:   Wed Oct 21 08:55:43 2026 +1100

    perldelta for -Duselongdouble on ARM64 noise reduction

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 3478513a26..95e8203f7c 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -254,7 +254,26 @@ L</Platform Support> section, instead.

 =item *

-XXX
+Fix some build noise and technical undefined behaviour with
+C<-Duselongdouble> builds on ARM64:
+
+=over
+
+=item *
+
+C<Configure> would detect C<double> format strings rather than the
+correct C<long double> format string as the format string for NV when NV
+was C<long double>, resulting in C<-Wformat> warnings.
+
+=item *
+
+F<perl.h> would disable C<USE_LONG_DOUBLE> when C<double> and C<long
+double> were the same size leaving NV as C<long double>.  This would
+result in calls to a C library function that expected a C<double>
+pointer being supplied a <long double> pointer, resulting in type
+mismatch warnings.
+
+=back

 =back