+dnl For -any- checks on $enable_all_components
+dnl use the following guildlines:
+dnl yes : --enable-all-components was specified, so error out if any
+dnl components do not pass configuration checks.
+dnl no : --disable-all-components was specified, so try to build the
+dnl --enable'd components, and error out if any do not pass
+dnl configuration checks.
+dnl "" : this option was not specified on the command line; try to
+dnl build all components that are not --with'd, but don't
+dnl error out if any component does not pass configuration checks.
+dnl
+dnl For each --enable-foo component, if that flag is not specified on
+dnl the command line, the related variable $enable_foo will be set to
+dnl $enable_all_components .
+