$ git clean -dfx \ && ./Configure -des -Dusedevel -Dcc='ccache cc' \ && make miniperl ... $ ./miniperl -le'for (1) { my $r = \$_; $$r++; print; print $$r; }' Modification of a read-only value attempted at -e line 1. $ git clean -dfx \ && ./Configure -des -Dusedevel -Dcc='ccache cc' -Dusethreads \ && make miniperl ... $ ./miniperl -le'for (1) { my $r = \$_; $$r++; print; print $$r; }' 1 2