A .ecm (minimal configuration) file cannot represent a configuration where
a package has been removed from the configuration first.
For example if you started with the default template and added
CYGPKG_POSIX, you would get a conflict because of having two signal
implementations present. This would be resolved by removing
CYGPKG_LIBC_SIGNALS from the config. A configuration like that cannot be
represented in a .ecm file.
This bug has moved to http://bugs.ecos.sourceware.org/show_bug.cgi?id=57324