* guix/build/gnu-bootstrap.scm (bootstrap-configure,
bootstrap-build, bootstrap-install): Treat the 'modules' argument as
a list of directories.
* gnu/packages/commencement.scm (bootar, gash-boot,
gash-utils-boot): Adjust call sites.
* guix/build/gnu-bootstrap.scm (bootstrap-configure): Add a 'name'
argument and use it to configure the PACKAGE_NAME variable.
* gnu/packages/commencement.scm (bootar, gash-boot,
gash-utils-boot): Use the new argument.