[Toybox] Oldconfig sed q, and basename gcc-ar -ar

[Denys Nykula]

Portage can't upgrade toybox with sed linked to toybox:

# make oldconfig
scripts/genconfig.sh
sed: bad pattern '/^\*\//q;/^config [A-Z]/,$p'@9 (;)
kconfig/conf -o Config.in
Config.in:5: can't open file "generated/Config.in"
make: *** [kconfig/Makefile:18: oldconfig] Error 1

Pkgsrc tries to remove basename suffix beginning with dash:

# toybox basename gcc-ar -ar
basename: Unknown option 'r' (see "basename --help")
# busybox basename gcc-ar -ar
gcc

Slightly different example, without visible -a involvement:

# toybox basename foo-bar -bar
basename: Unknown option 'bar' (see "basename --help")
# busybox basename foo-bar -bar
foo