The allegro library (liballeg.a) in this path, is a 'debug' build that Grayswandir generated.
Thus far, we have only been able to build ZC  2.50.x on Linux using this specific library.

This may require changing line 142 in CMakelists.txt from:
set(ALLEGROLIB alleg)
to
set(ALLEGROLIB alleg dl)

-ZoriaRPG (27th February, 2018)