perl: put perl dependencies in buildInputs instead of manually passing them to configure

Perl has an env hook[1]. Passing the paths manually without putting them
in buildInputs is harder to understand, plays less nicely with dev
shells, and is less build-generic.

Produced identical output on my x86_64-linux machine, and on my
aarch64-darwin machine was identical save for the derivation output path
which gets embedded into the .dylib Mach-O.

Change-Id: Ib313caa5a6f0b0e3154ce6f05379033920d0d290

perl/default.nix

@@ -36,15 +36,12 @@ perl.pkgs.toPerlModule (stdenv.mkDerivation {
       xz
       perl
       boost
+      perlPackages.DBI
+      perlPackages.DBDSQLite
     ]
     ++ lib.optional (stdenv.isLinux || stdenv.isDarwin) libsodium
     ++ lib.optional stdenv.isDarwin darwin.apple_sdk.frameworks.Security;
 
-  configureFlags = [
-    "--with-dbi=${perlPackages.DBI}/${perl.libPrefix}"
-    "--with-dbd-sqlite=${perlPackages.DBDSQLite}/${perl.libPrefix}"
-  ];
-
   enableParallelBuilding = true;
 
   postUnpack = "sourceRoot=$sourceRoot/perl";