Update BUILD.md after PR 5052

[dangell7]

High Level Overview of Change

Added the -Dxrpld=TRUE -Dtests=TRUE cmake flags to the BUILD.md steps. After PR #5052 I was not able to build rippled.

ninja: error: unknown target 'rippled'

Context of Change

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Performance (increase or change in throughput and/or latency)
• Tests (you added tests for code that already exists, or your new feature included in this PR)
• Documentation update
• Chore (no impact to binary, e.g. .gitignore, formatting, dropping support for older tooling)
• Release

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.3%. Comparing base (f3bcc65) to head (1178e39).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #5067   +/-   ##
=======================================
  Coverage     71.3%   71.3%           
=======================================
  Files          796     796           
  Lines        67031   67031           
  Branches     10885   10885           
=======================================
+ Hits         47808   47811    +3     
+ Misses       19223   19220    -3     

see 5 files with indirect coverage changes

[ximinez]

Since this is a relatively small change only to documentation, what do you think about treating this PR as trivial, so it only needs one approval?

[ximinez]

@dangell7 This now has two approvals. If you think it's ready to merge, please indicate such by putting the "Passed" label on it, or leaving a comment here to that effect.

[dangell7]

@ximinez Ah yes, I think treating this as trivial makes sense. Ready for merge.