## Issue Addressed
The documentation referring to build from source mismatches with the what gitworkflow uses.
aa5b7ef783/book/src/installation-source.md (L118-L120)
## Proposed Changes
Because the github workflow uses `cross` to build from source and for that build there is different env variable `CROSS_FEATURES` so need pass at the compile time.
## Additional Info
Verified that existing `-dev` builds does not contains the `minimal` spec enabled.
```bash
> docker run --rm --name node-5-cl-lighthouse sigp/lighthouse:latest-amd64-unstable-dev lighthouse --version
Lighthouse v3.4.0-aa5b7ef
BLS library: blst-portable
SHA256 hardware acceleration: true
Allocator: jemalloc
Specs: mainnet (true), minimal (false), gnosis (true)
```
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