Update autolock test to allow rebuilds

Rebuilds happen because the internal package solution generated when
autolocking is specialized to the current platform. This allows building
on platforms which portable lockdirs don't support by default, however
it means that packages built from a pre-existing portable lockdir need
to be rebuilt with the new build plan.

Signed-off-by: Stephen Sherratt <[email protected]>

Author: gridbugs

test/blackbox-tests/test-cases/pkg/pkg-lock-then-autolock.t

@@ -1,5 +1,4 @@
-Test that explicit locking followed by auto-locking produces equivalent results
-and does not trigger unnecessary rebuilds.
+Test that explicit locking followed by auto-locking produces equivalent results.
 
   $ . ./helpers.sh
   $ mkrepo
@@ -55,7 +54,7 @@ Create a project that depends on foo:
   > EOF
 
 Lock and build with explicit dune pkg lock:
-  $ dune pkg lock
+  $ dune_pkg_lock_normalized
   Solution for dune.lock:
   - foo.0.0.1
 
@@ -71,9 +70,12 @@ Remove the lock directory:
 Enable auto-locking:
   $ enable_pkg
 
-Build again - should auto-lock internally and NOT rebuild foo:
-  $ dune exec --display short bar 2>&1 | grep "Building" || echo "no rebuilds"
-  no rebuilds
+Build again - should auto-lock internally. Since the package solution is now
+private, it can be specialied to the current platform. This means that the
+build plan for the package has changed from the original portable solution
+generated by 'dune pkg lock', and so the dependencies must be rebuilt.
+  $ dune exec --display short bar 2>&1 | grep "Building"
+      Building foo.0.0.1
 
   $ dune exec bar
   Hello from foo 0.0.1!