libbfd: add CC_FOR_BUILD into depends
libbfd: add CC_FOR_BUILD into depends

Without the change cross-compiling libbfd fails as:

      GEN      doc/bfdver.texi
      CCLD     doc/chew.stamp
    ...-bash-5.1-p16/bin/bash: line 1: gcc: command not found

Tested on `pkgsCross.riscv64.libbfd`.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs