fix build issue due to missing autoreconf, fix quoting in environment…

[ogra1]

… variables (new snapcraft is a bit stricter here)

[dilyn-corner]

FYI this may have just been a duplicate of this.

[benfrancis]

@mr-cal Has canonical/snapcraft#5051 made it into the stable channel of the snapcraft snap yet?

When I try to run snapcraft without this patch (at f45dd83) using snapcraft 8.4.2 (released on the stable channel today) I still get an error:

ad snapcraft.yaml content:                                                    
- Value error, value must be a list of Annotated: [{'npm_config_unsafe_perm': True}, {'NODE_ENV': 'dev'}, {'CPPFLAGS': '$CPPFLAGS -DPNG_ARM_NEON_OPT=0'}] (in field 'parts.webthings-gateway.build-environment')                               
Full execution log: '/home/tola/.local/state/snapcraft/log/snapcraft-20241009-182629.208188.log'      

I assume the error is due to a change in snapcraft because the snap had previously been building locally at f45dd83 (before this patch) with an earlier version of snapcraft.