Fix test build script lib path and improve adjust_dotfile docs

The generated GNU Stow binary had a 'use lib' path pointing to a
nonexistent install directory, causing tests to use system stow
libraries instead of 2.4.1. Fixed by patching the lib path after make.

Also expanded adjust_dotfile docstring to document edge cases.

Author: isarandi

bin/stow

@@ -320,6 +320,12 @@ def adjust_dotfile(pkg_node):
     """
     Converts dot-X to .X for dotfiles mode.
     Used when stowing with --dotfiles flag.
+
+    Only transforms 'dot-X' to '.X' when X starts with a non-dot character.
+    This prevents transforming:
+    - 'dot-' (no character after dash)
+    - 'dot-.' (next char is dot)
+    - 'dot-..' (next char is dot)
     """
     # Perl: (my $adjusted = $pkg_node) =~ s/^dot-([^.])/.$1/;
     # Matches "dot-" followed by a character that is not a dot

tests/get_gnu_stow_for_testing_identical_behavior.sh

@@ -18,4 +18,9 @@ cd "$DEST_DIR"
 ./configure --prefix="$DEST_DIR/install" >/dev/null
 make bin/stow bin/chkstow lib/Stow.pm lib/Stow/Util.pm >/dev/null
 
+# Fix the lib path in bin/stow to use the local lib directory instead of install
+# The generated bin/stow has 'use lib "...install/share/perl/..."' which doesn't exist
+# after just 'make' (without 'make install'). Point it to the local lib/ instead.
+sed -i 's|use lib "[^"]*";|use lib "'"$DEST_DIR"'/lib";|' bin/stow bin/chkstow
+
 echo "Perl stow ${VERSION} built in ${DEST_DIR}"