z80asm: public constants not being listed in global .def file

[aralbrec]

Sample program:

org 65000

PUBLIC program

PUBLIC asm_BIFROST2_start
PUBLIC asm_BIFROST2_stop

DEFC asm_BIFROST2_start              = $C9A9 ;   asm_BIFROST2
DEFC asm_BIFROST2_stop               = $C9B2 ;   asm_BIFROST2
DEFC asm_BIFROST2_showNext2Tiles     = $C9C2 ;   asm_BIFROST2
DEFC asm_BIFROST2_showNextTile       = $C9C5 ;   asm_BIFROST2
DEFC asm_BIFROST2_showTilePosH       = $C9E3 ;   asm_BIFROST2
DEFC asm_BIFROST2_drawTileH          = $CA02 ;   asm_BIFROST2
DEFC _BIFROST2_TILE_IMAGES           = $CA17 ;   asm_BIFROST2
DEFC _BIFROST2_ISR_HOOK              = $FD29 ;   asm_BIFROST2
DEFC asm_BIFROST2_fillTileAttrH      = $FD3D ;   asm_BIFROST2

program:
ret

Assemble with:
z80asm -b -s -g -m zzz.asm

When assembled, the unreferenced local symbols ("asm_BIFROST2_showNext2Tiles" through "asm_BIFROST2_fillTileAttrH") are not listed anywhere in symbol files, map files or by z80nm on the object file "zzz.o". That is expected behaviour.

The two publicly exported constants ("asm_BIFROST2_start" and "asm_BIFROST2_stop") show up in the map file, the sym file, and by z80nm on "zzz.o" where they are marked as global as expected. But they are missing from the global zzz.def file.