Document Build's run-time dependencies

perl-Module-Build.spec

@@ -83,6 +83,13 @@ Requires:       perl(Test::Harness)
 Requires:       perl(Pod::Html)
 Requires:       perl(Pod::Man) >= 2.17
 Requires:       perl(Pod::Text)
+# Run-time for generated Build scripts from Build.PLs:
+# Those are already found by dependency generator. Just make sure they
+# present.
+# Cwd
+# File::Basename
+# File::Spec
+# strict
 
 %{?perl_default_filter}
 # Remove under-specified dependencies