[PD-dev] Help for macro syntax in m4 config files.

[nicolas.danet at free.fr]

Hi list,

I'm not a m4/autotools expert and such i'm a bit stuck with codes below (from "m4/universal.m4")

https://github.com/pure-data/pure-data/blob/master/m4/universal.m4#L68

$1[]_CFLAGS="$[]$1[]_CFLAGS $_pd_universal"
$1[]_LDFLAGS="$[]$1[]_LDFLAGS $_pd_universal"

What's the meaning of the "$1[]" and "$[]$1[]" syntaxes? 

I guess it is related to macro expansion (to properly obtained ARCH_CFLAGS and ARCH_LDFLAGS), but is that anybody could give me some explanations about that trick?