linux_testing (5.2.0-rc1): fix build, include 'cpio' in nativeBuildInputs

81d4e65891 automatically bumped
linux_testing to 5.2.0-rc1, but the 5.2 merge window included a new
feature adding compressed headers for compiled kernels into
/proc/kheaders.tar.xz

See 43d8ce9d65

This feature requires 'cpio' to now be included in nativeBuildInputs
since it's used to construct that archive.

This wasn't caught by Hydra since we turn off build of linuxPackages,
but ideally we should at least build the kernel in the future
(linux_testing itself.)

Signed-off-by: Austin Seipp <aseipp@pobox.com>

pkgs/os-specific/linux/kernel/manual-config.nix

@@ -1,5 +1,5 @@
 { buildPackages, runCommand, nettools, bc, bison, flex, perl, rsync, gmp, libmpc, mpfr, openssl
-, libelf
+, libelf, cpio
 , utillinux
 , writeTextFile
 }:
@@ -284,10 +284,11 @@ stdenv.mkDerivation ((drvAttrs config stdenv.hostPlatform.platform kernelPatches
 
   depsBuildBuild = [ buildPackages.stdenv.cc ];
   nativeBuildInputs = [ perl bc nettools openssl rsync gmp libmpc mpfr ]
-      ++ optional (stdenv.hostPlatform.platform.kernelTarget == "uImage") buildPackages.ubootTools
-      ++ optional (stdenv.lib.versionAtLeast version "4.14") libelf
-      ++ optional (stdenv.lib.versionAtLeast version "4.15") utillinux
+      ++ optional  (stdenv.hostPlatform.platform.kernelTarget == "uImage") buildPackages.ubootTools
+      ++ optional  (stdenv.lib.versionAtLeast version "4.14") libelf
+      ++ optional  (stdenv.lib.versionAtLeast version "4.15") utillinux
       ++ optionals (stdenv.lib.versionAtLeast version "4.16") [ bison flex ]
+      ++ optional  (stdenv.lib.versionAtLeast version "5.2")  cpio
       ;
 
   hardeningDisable = [ "bindnow" "format" "fortify" "stackprotector" "pic" "pie" ];