meson: Allow user to specify a custom python shebang
In wolfi-os, we support multiple co-installed /usr/bin/python3.X interpreters where /usr/bin/python3 could be a symlink to any one of them - or not exist at all. For this reason, we prefer that system-installed python scripts use an explicit shebang.
Today, if I specify -Dpython=python3.13, the package will end up
with a #!/usr/bin/env python3
shebang. Instead of adding more
autodetect logic, let's just provide a configuration option to
specify the one we want.
Signed-off-by: dann frazier dann.frazier@chainguard.dev