neovim: fix gperf error on dev-version

[ 50%] Generating auto/api/private/dispatch_wrappers.c.generated.h, ../../include/api/private/dispatch_wrappers.h.generated.h
[ 50%] Generating auto/funcs.generated.h, ../../funcs_data.mpack
/nix/store/xn5gv3lpfy91yvfy9b0i7klfcxh9xskz-bash-4.4-p19/bin/bash: ../../../.deps/usr/bin/gperf: No such file or directory