TL2024 from .iso fail under cygwin (win11 pro)

[Karl Berry]

    > You are using Cygwin, and this problem could arise if you haven't 
    > installed Cygwin's wget. See the section of the TeX Live documentation 
    > about installation under Cygwin.

It feels weird to me to put in this sort of vague platform-specific
message instead of detecting and/or solving the actual error, but ok, I
guess it's an improvement. And it seems the whole problem does not arise
often. Hope it comes out ok ... --thanks, karl.

--- TLPDB.pm	(revision 71090)
+++ TLPDB.pm	(working copy)
@@ -362,9 +362,21 @@
         # do nothing
       } else {
         unlink($tlpdbfile);
-        tldie(  "$0: TLPDB::from_file could not initialize from: $path\n"
-              . "$0: Maybe the repository setting should be changed.\n"
-              . "$0: More info: https://tug.org/texlive/acquire.html\n");
+        my $diemsg = <<END_DOWNLOAD_FAILURE_MSG;
+$0: TLPDB::from_file could not get texlive.tlpdb from: $path
+Maybe the repository setting should be changed.
+More info: https://tug.org/texlive/acquire.html
+END_DOWNLOAD_FAILURE_MSG
+        if ($^O eq 'cygwin') {
+          $diemsg .= <<END_CYGWIN_WGET_MSG;
+
+It seems you are using Cygwin, and this problem could arise if you haven't 
+installed Cygwin's wget. See the TeX Live Guide information on Cygwin
+for required and recommended packages:
+  https://tug.org/texlive/doc/texlive-en/texlive-en.html#cygwin
+END_CYGWIN_WGET_MSG;
+        }
+        tldie($diemsg);
       }
     }
     # if we are still here, then either the xz version was downloaded