xorg-server: fix XKB_BINDIR usage (close #8993)
xorg-server: fix XKB_BINDIR usage (close #8993)

Previously, XKB_BINDIR was read inside a loop over the program
arguments, so was only read if it had arguments that weren't matched by
the first some number of checks.

SymbiFlow/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,triton/triton,SymbiFlow/nixpkgs,triton/triton,NixOS/nixpkgs,triton/triton,NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,triton/triton,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,SymbiFlow/nixpkgs,NixOS/nixpkgs,triton/triton,SymbiFlow/nixpkgs,SymbiFlow/nixpkgs