.github/workflows/extract-sage-local.sh: Use PREFIX

.github/workflows/extract-sage-local.sh

@@ -1,26 +1,27 @@
 #!/usr/bin/env bash
 # to be run from $SAGE_ROOT, with arguments sage-local-${{ env.PREVIOUS_STAGES }}.tar
 
+if [ -z "$PREFIX" ]; then
+    PREFIX=$(pwd)/local
+fi
+
 # Show all tar files
 ls -l $*
 
 # We specifically use the cygwin tar so that symlinks are saved/restored correctly on Windows.
 for a in $*; do
     echo Extracting $a
-    tar xf $a
+    (cd / && tar xf -) < $a
     rm -f $a
 done
 
-# Also get rid of the stages that were not extracted
-rm -f sage-local-*.tar
-
 # We set the installation records to the same mtime so that no rebuilds due to dependencies
 # among these packages are triggered.
-(cd local/var/lib/sage/installed/ && touch .dummy && touch --reference=.dummy *)
+(cd "$PREFIX"/var/lib/sage/installed/ && touch .dummy && touch --reference=.dummy *)
 
 # Show what has been built already.
-ls -l local local/var/lib/sage/installed/
+ls -l "$PREFIX" "$PREFIX"/local/var/lib/sage/installed/
 df -h
 
 # Rebase!
-src/bin/sage-rebase.sh local
+src/bin/sage-rebase.sh "$PREFIX"