libahp_xc doesn't install and indi-ahp-correlator fail to build

[nouspiro]

I am building latest indilib on my raspberry pi. Last week it started to fail building indi-ahp-correlator on undefined functions.
Turn out that ahp_xc.h that was installed in /usr/include/ahp was old version. Rebuilding didn't updated this header file. I must add these lines into IF(BUILD_LIBS) section so libahp_xc get installed during lib building phase and then indi-ahp-correlator can build correctly

#if (WITH_AHP_CORRELATOR)
add_subdirector(libahp_xc)
endif(WITH_AHP_CORRELATOR)

[knro]

@iliaplatone Can you please check?

[iliaplatone]

I made a pull request, it now stops at astrolink build

[iliaplatone]

The library was not being installed in CircleCI
PR is #240

[nouspiro]

That merge request doesn't fix issue. It still doesn't build/install libahp_xc with BUILD_LIBS=1. Instead it get build/installed during normal driver build but then it still doesn't build indi-ahp-correlator