More warnings

[pb-cdunn]

This is with the tip of your own repository (not our fork):

datander.c: In function ‘main’:
datander.c:270:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

align.c: In function ‘Compute_Alignment’:
align.c:4424:17: warning: ‘L’ may be used uninitialized in this function [-Wmaybe-uninitialized]
           n  = L/sizeof(uint16);
                 ^

DB.c: In function ‘Trim_DB’:
DB.c:691:14: warning: ‘css’ may be used uninitialized in this function [-Wmaybe-uninitialized]
           if (css)
              ^