perl: Cross-compile: patch miniperl for gcc7

pkgs/development/interpreters/perl/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurlBoot, buildPackages, enableThreading ? stdenv ? glibc }:
+{ lib, stdenv, fetchurlBoot, buildPackages, enableThreading ? stdenv ? glibc, fetchpatch }:
 
 with lib;
 
@@ -133,12 +133,19 @@ let
       sha256 = "072j491rpz2qx2sngbg4flqh4lx5865zyql7b9lqm6s1kknjdrh8";
     };
 
-    # Hacky! But not sure how else we can access a native-targeted gcc6
     # https://github.com/arsv/perl-cross/issues/60
-    nativeBuildInputs = [ buildPackages.buildPackages.gcc6 ];
+    perl-cross-gcc7-patch = fetchpatch {
+      url = "https://github.com/arsv/perl-cross/commit/07208bc1707b8be3ea170c62c59120020cf0f87f.patch";
+      sha256 = "1gh8w9m5if2s0lrx2x8f8grp74d1l6d46m8jglpjm5a1kf55j810";
+    };
+
+    depsBuildBuild = [ buildPackages.stdenv.cc ];
 
     postUnpack = ''
       unpackFile ${perl-cross-src}
+      cd perl-cross-*
+      patch -Np1 -i ${perl-cross-gcc7-patch}
+      cd ..
       cp -R perl-cross-${crossVersion}/* perl-${version}/
     '';