The ATmega8L is the low-speed ATmega8 and can only run up to 8 MHz. I expect the fuse settings will be the same as for the ATmega8 but with the different processor and lower clock speed.
This is the current entry for the Arduino NG and earlier models which could have an ATmega8
##############################################################
atmegang.name=Arduino NG or older
atmegang.upload.tool=avrdude
atmegang.upload.protocol=arduino
atmegang.upload.speed=19200
atmegang.bootloader.tool=avrdude
atmegang.bootloader.unlock_bits=0x3F
atmegang.bootloader.lock_bits=0x0F
atmegang.build.mcu=atmegang
atmegang.build.f_cpu=16000000L
atmegang.build.board=AVR_NG
atmegang.build.core=arduino
atmegang.build.variant=standard
## Arduino NG or older w/ ATmega168
## --------------------------------
atmegang.menu.cpu.atmega168=ATmega168
atmegang.menu.cpu.atmega168.upload.maximum_size=14336
atmegang.menu.cpu.atmega168.upload.maximum_data_size=1024
atmegang.menu.cpu.atmega168.bootloader.low_fuses=0xff
atmegang.menu.cpu.atmega168.bootloader.high_fuses=0xdd
atmegang.menu.cpu.atmega168.bootloader.extended_fuses=0xF8
atmegang.menu.cpu.atmega168.bootloader.file=atmega/ATmegaBOOT_168_ng.hex
atmegang.menu.cpu.atmega168.build.mcu=atmega168
## Arduino NG or older w/ ATmega8
## ------------------------------
atmegang.menu.cpu.atmega8=ATmega8
atmegang.menu.cpu.atmega8.upload.maximum_size=7168
atmegang.menu.cpu.atmega8.upload.maximum_data_size=1024
atmegang.menu.cpu.atmega8.bootloader.low_fuses=0xdf
atmegang.menu.cpu.atmega8.bootloader.high_fuses=0xca
atmegang.menu.cpu.atmega8.bootloader.extended_fuses=
atmegang.menu.cpu.atmega8.bootloader.file=atmega8/ATmegaBOOT-prod-firmware-2009-11-07.hex
atmegang.menu.cpu.atmega8.build.mcu=atmega8
##############################################################
I would guess that this might work for the ATmega8L.
I changed ".build.f_cpu=16000000L" to ".build.f_cpu=8000000L".
I changed ".upload.speed=19200" to ".upload.speed=9600" because the bootloader will be running at half speed.
I changed ".build.mcu=atmega8" to ".build.mcu=atmega8l" so avrdude will expect the 8L signature.
Note: I don't know if the avrdude that comes with the Arduino IDE knows about the ATmega8L processor.
##############################################################
arduino8l.name=Arduino w/ ATmega8L
arduino8l.upload.tool=avrdude
arduino8l.upload.protocol=arduino
arduino8l.upload.speed=9600
arduino8l.upload.maximum_size=7168
arduino8l.upload.maximum_data_size=1024
arduino8l.bootloader.tool=avrdude
arduino8l.bootloader.unlock_bits=0x3F
arduino8l.bootloader.lock_bits=0x0F
arduino8l.bootloader.low_fuses=0xdf
arduino8l.bootloader.high_fuses=0xca
arduino8l.bootloader.extended_fuses=
arduino8l.bootloader.file=atmega8/ATmegaBOOT-prod-firmware-2009-11-07.hex
arduino8l.build.mcu= atmega8l
arduino8l.build.f_cpu=8000000L
arduino8l.build.board=AVR_NG
arduino8l.build.core=arduino
arduino8l.build.variant=standard
##############################################################