ensure old specs file is removed before build #218

Job	Run time
build (ubuntu-latest, clean, i386-pc-msdosdjgpp, binutils gcc djgpp-2.05 watt32)	23m 24s
build (ubuntu-latest, clean, i386-pc-msdosdjgpp, binutils gcc djgpp-cvs watt32)	23m 48s
build (ubuntu-latest, clean, i386-pc-msdosdjgpp, gdb)	7m 2s
build (ubuntu-latest, clean, arm-eabi, binutils gcc newlib)	30m 25s
build (ubuntu-latest, clean, arm-eabi, gdb)	13m 35s
build (ubuntu-latest, clean, avr, binutils gcc avr-libc)	50m 26s
build (ubuntu-latest, clean, avr, gdb avarice simulavr avrdude)	1m 16s
build (ubuntu-latest, clean, ia16-elf, binutils gcc newlib)	10m 8s
build (macos-latest, clean, i386-pc-msdosdjgpp, binutils gcc djgpp-2.05 watt32)	48s
build (macos-latest, clean, i386-pc-msdosdjgpp, binutils gcc djgpp-cvs watt32)	50s
build (macos-latest, clean, i386-pc-msdosdjgpp, gdb)	54s
build (macos-latest, clean, arm-eabi, binutils gcc newlib)	48s
build (macos-latest, clean, arm-eabi, gdb)	55s
build (macos-latest, clean, avr, binutils gcc avr-libc)	1m 1s
build (macos-latest, clean, avr, gdb avarice simulavr avrdude)	58s
build (macos-latest, clean, ia16-elf, binutils gcc newlib)	46s
	2h 47m 4s

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