Initial make fails with error about Python

[riban-bw]

Following the build instructions in the README I get the following error:

make: Entering directory '/home/brian/projects/libopencm3_test/libopencm3'
  GENHDR  include/libopencm3/stm32/f0/irq.json
/usr/bin/env: ‘python’: No such file or directory
make: *** [Makefile:59: include/libopencm3/stm32/f0/irq.json.genhdr] Error 127
make: Leaving directory '/home/brian/projects/libopencm3_test/libopencm3'

I wonder whether this is due to the build process depending on Python2 which is now obsolute. Python3 executables tend to be called python3 whereas Python2 were just called python. (It is a shame that distros haven't yet changed the default name / alias for python=>python3.)

I see there are many scripts that have #!/usr/bin/env python. Updating each of these to use python3 advances the build but still failures:

make[1]: arm-none-eabi-gcc: No such file or directory

It looks like the cross compiler installed on my system differs (in location?) from that expected by the build system. Maybe the README should describe this dependancy?