New review comment by basploeger on void-packages repository

https://github.com/void-linux/void-packages/pull/36654#discussion_r862099852

Comment:
This line is needed to work around a problem in the package's configure/make setup. If I omit it, then `./xbps-src install apcupsd` fails with:

```
  COPY  apcupsd => /destdir//apcupsd-3.14.14/usr/bin/apcupsd
/usr/bin/install: target '/destdir//apcupsd-3.14.14/usr/bin/apcupsd' is not a directory
make[2]: *** [Makefile:49: install-base] Error 1
make[1]: *** [../autoconf/targets.mak:69: install] Error 2
make: *** [autoconf/targets.mak:111: src_DIR] Error 2
=> ERROR: apcupsd-3.14.14_1: do_install: '${make_cmd} DESTDIR=${DESTDIR} ${make_install_args} ${make_install_target}' exited with 2
=> ERROR:   in do_install() at common/build-style/gnu-configure.sh:40
```

The problem is that the `install` command that `make` is executing, gets an argument `strip` rather than `--strip` (I am not sure why, but this seems an error in the configure/make files). This wrong argument means `install` tries to copy files `strip` and `apcupsd` into a _directory_ `/usr/bin/apcupsd`, which is not the intention. The intention is to copy file `apcupsd` to file `/usr/bin/apcupsd`. 

The only way I found to work around this error, is by clearing the env var `STRIP`, which ensures the `strip` argument is not passed to `install`.