case:
MKBFD If set to "no", disables building of libbfd, libiberty,
and all things that depend on them (binutils/gas/ld, gdb,
dbsym, mdsetimage).
MKGDB If set to "no", disables bulding of gdb.
MKGCC If set to "no", disables building of gcc and the
gcc-related libraries (libg2c, libgcc, libobjc, libstdc++).
These are useful for building platforms for which either of the following
situations are true:
(1) You have no userland from which to run toolchain2netbsd
in order to build the appropriate toolchain build framework.
(2) The platform which you are building requires a newer set
of tools than are currently in the tree (e.g. x86-64, ia64).