Examples on real ports:
1. graphics/khronos-texture
Without this feature:
```
OPTIONS_DEFAULT_aarch64= NEON
OPTIONS_DEFAULT_amd64= SSE2
OPTIONS_DEFAULT_armv6= NONE
OPTIONS_DEFAULT_armv7= NEON
OPTIONS_DEFAULT_i386= NONE
OPTIONS_DEFAULT_mips= NONE
OPTIONS_DEFAULT_mips64= NONE
OPTIONS_DEFAULT_powerpc= NONE
OPTIONS_DEFAULT_powerpc64= NONE
OPTIONS_DEFAULT_powerpc64le= NONE
OPTIONS_DEFAULT_powerpcspe= NONE
OPTIONS_DEFAULT_riscv64= NONE
OPTIONS_DEFAULT_riscv64sf= NONE
```
With this feature:
```
OPTIONS_DEFAULT_aarch64= NEON
OPTIONS_DEFAULT_amd64= SSE2
OPTIONS_DEFAULT_armv7= NEON
OPTIONS_DEFAULT_OTHER_ARCHES= NONE
```
2. sysutils/nut{,-devel} (https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=277089)
Without:
```
OPTIONS_DEFAULT_amd64= FREEIPMI
OPTIONS_DEFAULT_i386= FREEIPMI
OPTIONS_DEFAULT_powerpc= FREEIPMI
OPTIONS_DEFAULT_powerpc64= FREEIPMI
OPTIONS_DEFAULT_powerpc64le= FREEIPMI
OPTIONS_DEFAULT_riscv64= FREEIPMI
OPTIONS_DEFAULT_riscv64sf= FREEIPMI
```
With:
```
OPTIONS_DEFAULT_aarch64=
OPTIONS_DEFAULT_armv6=
OPTIONS_DEFAULT_armv7=
OPTIONS_DEFAULT_OTHER_ARCHES= FREEIPMI
```
Tested with `make -V OPTIONS_DEFAULT` and build in poudriere.