[nextcloud] Including imagemagick extension?

I've tried to add it to the build with:

```
BUILD_DEPS=... \
    imagemagick-dev \
    pcre-dev

NORMAL_APKS=...\
    imagemagick

pecl install ... \
    imagick

echo "extension=imagick.so" > /etc/php7.1/conf.d/imagick.ini
```

However everytime php runs (cli and fpm), I get a segmentation fault. Any help would be appreciated.
