ipxe: support renaming targets and add several

This allows to build several targets with conflicting names.
UEFI version of USB image is now built, and so is option ROM.

pkgs/tools/misc/ipxe/default.nix

@@ -1,23 +1,28 @@
-{ stdenv, lib, fetchgit, perl, cdrkit, syslinux, xz, openssl, gnu-efi
+{ stdenv, lib, fetchgit, perl, cdrkit, syslinux, xz, openssl, gnu-efi, mtools
 , embedScript ? null
+, additionalTargets ? {}
 }:
 
 let
   date = "20190318";
   rev = "ebf2eaf515e46abd43bc798e7e4ba77bfe529218";
-  targets = (lib.optional stdenv.isx86_64 "bin-x86_64-efi/ipxe.efi") ++ [
-    "bin/ipxe.dsk"
-    "bin/ipxe.usb"
-    "bin/ipxe.iso"
-    "bin/ipxe.lkrn"
-    "bin/undionly.kpxe"
-  ];
+  targets = additionalTargets // lib.optionalAttrs stdenv.isx86_64 {
+    "bin-x86_64-efi/ipxe.efi" = null;
+    "bin-x86_64-efi/ipxe.efirom" = null;
+    "bin-x86_64-efi/ipxe.usb" = "ipxe-efi.usb";
+  } // {
+    "bin/ipxe.dsk" = null;
+    "bin/ipxe.usb" = null;
+    "bin/ipxe.iso" = null;
+    "bin/ipxe.lkrn" = null;
+    "bin/undionly.kpxe" = null;
+  };
 in
 
 stdenv.mkDerivation {
   name = "ipxe-${date}-${builtins.substring 0 7 rev}";
 
-  buildInputs = [ perl cdrkit syslinux xz openssl gnu-efi ];
+  nativeBuildInputs = [ perl cdrkit syslinux xz openssl gnu-efi mtools ];
 
   src = fetchgit {
     url = https://git.ipxe.org/ipxe.git;
@@ -49,11 +54,14 @@ stdenv.mkDerivation {
 
   preBuild = "cd src";
 
-  buildFlags = targets;
+  buildFlags = lib.attrNames targets;
 
   installPhase = ''
     mkdir -p $out
-    cp ${lib.concatStringsSep " " targets} $out
+    ${lib.concatStringsSep "\n" (lib.mapAttrsToList (from: to:
+      if to == null
+      then "cp -v ${from} $out"
+      else "cp -v ${from} $out/${to}") targets)}
 
     # Some PXE constellations especially with dnsmasq are looking for the file with .0 ending
     # let's provide it as a symlink to be compatible in this case.
@@ -67,6 +75,6 @@ stdenv.mkDerivation {
       homepage = http://ipxe.org/;
       license = licenses.gpl2;
       maintainers = with maintainers; [ ehmry ];
-      platforms = platforms.all;
+      platforms = [ "x86_64-linux" "i686-linux" ];
     };
 }