#795 simplified env code makes unnable to build for glib 2.24 to 2.30

[PICCORO Lenz McKAY]

the commit 51c10f9bc4d38962b6eaeef229d502ca38b8a155 that was for simplify code env now makes unnable to compile for blig between versions 2.22 to 2.31.. so many special builds for proyect can able to use lxdm...

as i said log time ago, if a "light" are not able to compile, users will swicht, i noted as debian and winbuntu uses now lightdm event lxdm.. in lxde metapackages...

please help to made backguard compatible so i can promote lxde as far possible and beyond, also i can use some important componets such lxdm... in last features for older hardware and liraries without recompiling newer versions...

its a hard history of "keep in fashion stupid up to day"