Does not build on Apple M SOC

[thebigcorporation]

using brew on Apple M1.

This references PR 7dc875b

The PR builds on Intel Mac and Linux of course, but fails on M1 as follows:

#10 4.028 make[1]: Entering directory '/usr/src'
#10 4.028 gcc -DHAVE_CONFIG_H -I.     -g -O2 -ggdb -Wall -march=core2 -MT cmdline-utils.o -MD -MP -MF .deps/cmdline-utils.Tpo -c -o cmdline-utils.o cmdline-utils.c
#10 4.031 cc1: error: unknown value 'core2' for '-march'
#10 4.031 cc1: note: valid arguments are: armv8-a armv8.1-a armv8.2-a armv8.3-a armv8.4-a armv8.5-a armv8.6-a armv8-r native
#10 4.032 make[1]: Leaving directory '/usr/src'
#10 4.032 make[1]: *** [Makefile:460: cmdline-utils.o] Error 1
#10 4.033 make: *** [Makefile:327: all] Error 2
#10 ERROR: executor failed running [/bin/sh -c autoupdate && autoreconf && ./configure && make && make install]: exit code: 2
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 > [builder 6/6] RUN autoupdate && autoreconf && ./configure && make && make install:
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executor failed running [/bin/sh -c autoupdate && autoreconf && ./configure && make && make install]: exit code: 2
make: *** [docker] Error 1