Index: apps/build.tcl
===================================================================
diff -u -N -rb146d7e3ac355b7afdb7d3d1249d138c4ab04ee9 -r2edfa21fb74866cf966a742b99d014a8881ce932
--- apps/build.tcl	(.../build.tcl)	(revision b146d7e3ac355b7afdb7d3d1249d138c4ab04ee9)
+++ apps/build.tcl	(.../build.tcl)	(revision 2edfa21fb74866cf966a742b99d014a8881ce932)
@@ -1,6 +1,12 @@
+# w/o tls
 # linux: https://kitcreator.rkeene.org/kits/840dec4286102c869d85bae3b0dcd32565e7bf12/tclkit
-# osx: https://kitcreator.rkeene.org/kits/6967b89da1f6af7b12cdc82819f3bdb13a661242/tclkit
+# macos: https://kitcreator.rkeene.org/kits/6967b89da1f6af7b12cdc82819f3bdb13a661242/tclkit
 
+# w/ tls
+# linux: http://kitcreator.rkeene.org/kits/c8fe6fba3323b12b924b4a0716609abbaa00822c/tclkit
+# macos: http://kitcreator.rkeene.org/kits/31eaf9ae17e769609700b41d1d3c9abeda27510d/tclkit
+# win: http://kitcreator.rkeene.org/kits/32c6369ff6ef02a685b75854237635d4a3d56611/tclkit.exe
+
 package require http
 package require tar
 package require platform
@@ -10,26 +16,46 @@
   set INSTALLDIR [file join $HOMEDIR install]
 
   cd $HOMEDIR
+
+  set URL https://core.tcl-lang.org/tcl/tarball/$tarball?uuid=$TCLTAG
   
-  set fh [open $tarball wb+]
-  try {
+  if {![catch {package require tls}]} {
+    
+    http::register https 443 [list ::tls::socket -tls1 1]
 
-    ::http::geturl http://core.tcl.tk/tcl/tarball/$tarball?uuid=$TCLTAG \
-        -binary true \
-        -channel $fh
+    set fh [open $tarball wb+]
+    try {
+      
+      ::http::geturl $URL \
+          -binary true \
+          -channel $fh
+      
+      seek $fh 0
+      zlib push gunzip $fh
+      ::tar::untar $fh -chan
+      
+    } on error {e opts} {
+      file delete -force tcl
+      return -options $opts $e
+    } finally {
+      close $fh
+      file delete -force $tarball
+    }
+  } else {
 
-    seek $fh 0
-    zlib push gunzip $fh
-    ::tar::untar $fh -chan
-    
-  } on error {e opts} {
-    file delete -force tcl
-    return -options $opts $e
-  } finally {
-    close $fh
-    file delete $tarball
+    # fall back to using curl
+    exec >@stdout 2>@stderr bash -lc "curl -L -k -o $tarball $URL"
+
+    set fh [open $tarball rb]
+    try {
+      zlib push gunzip $fh
+      ::tar::untar $fh -chan
+    } finally {
+      close $fh
+      file delete -force $tarball
+    }
   }
-  
+
   # exec tar -xzf tcl.tar.gz
   # https://stackoverflow.com/questions/22333745/how-does-tcl-exec-work-exactly