al_get_allegro_version - Allegro 5 API

       Returns  the  (compiled) version of the Allegro library, packed into a single integer as groups of 8 bits
       in the form (major << 24) | (minor << 16) | (revision << 8) | release.

       You can use code like this to extract them:

              uint32_t version = al_get_allegro_version();
              int major = version >> 24;
              int minor = (version >> 16) & 255;
              int revision = (version >> 8) & 255;
              int release = version & 255;

       The release number is 0 for an unofficial version and 1 or greater for an official release.  For  example
       “5.0.2[1]”  would  be the (first) official 5.0.2 release while “5.0.2[0]” would be a compile of a version
       from the “5.0.2” branch before the official release.

Allegro reference manual                                                         al_get_allegro_version(3alleg5)

       al_get_allegro_version - Allegro 5 API

              #include <allegro5/allegro.h>

              uint32_t al_get_allegro_version(void)