Installs from the gem dependencies files in the :gemdeps option in options, yielding to the block as in install.
If :without_groups is given in the options, those groups in the gem dependencies file are not used. See Gem::Installer for other options.
Builds and installs the Gem::Specification spec into the user dir
Installs the provided default specs including writing the spec file
Install the provided default specs
Looks up the latest specification for dependency and adds it to the always_install list.
Returns true if this gem is installable for the current platform.
Returns true if this gem is installable for the current platform.
Returns true if this specification is installable on this platform.
Add the install/update options to the option parser.