agda2hs locate doesn't work with the nix build

[liesnikov]

Steps to reproduce:

agda2hs $ nix build
agda2hs $ ./result/bin/agda2hs locate
/home/user/agda2hs/locate:1,1-1
Cannot read file /home/user/agda2hs/locate
Error: /home/user/agda2hs/locate: openBinaryFile: does not exist (No such file or directory)

This is due to the fact that agda2hs is wrapped in the process to pass in some flags, see

agda2hs/agda2hs.nix

Lines 20 to 23 in 84c0c36

	makeWrapper ${agda2hs}/bin/agda2hs $out/bin/agda2hs \
	--add-flags "--with-compiler=${ghc}/bin/ghc" \
	--add-flags "--library-file=${library-file}" \
	--add-flags "--local-interfaces"