Shell scripts should be executable so that meson reports their
invocation succinctly (does not print 'sh' '-e').
Python scripts should not be executable so that meson does the
detection of the right python binary itself.
Add -u everywhere to catch potential errors.
This is a very straightforward conversion of the rules in Makefile.am.
Generated objects (on arm64) are identical.
The only difference in executed commands is that automake uses ld -m
elf_x86_64, without us specifying the -m option anywhere. I suspect that
using the default for the given linker should be OK, so it's fine to just
skip it.
bleep_blop