ruby Install ruby tests that can only be run after ruby is installed Use the dev-libs/libedit library to provide the readline extension, used for instance by the irb tool. This flag will take precedence over the readline USE flag. If neither libedit nor readline USE flags are enabled, the readline extension will not be built (and irb will lose line editing functionality). Use the sys-libs/readline library to provide the readline extension, used for instance by the irb tool. This flag is meaningful only if the libedit USE flag is disabled. If neither libedit nor readline USE flags are enabled, the readline extension will not be built (and irb will lose line editing functionality). Add support for TCMalloc provided by dev-util/google-perftools EXPERIMENTAL Enables fast threading routines. Removes support for callcc.