libcgroup: fix static build (#404243)

pkgs/by-name/li/libcgroup/package.nix

@@ -5,7 +5,9 @@
   pam,
   bison,
   flex,
+  enableSystemd ? lib.meta.availableOn stdenv.hostPlatform systemdLibs,
   systemdLibs,
+  musl-fts,
   autoreconfHook,
 }:
 
@@ -21,15 +23,30 @@ stdenv.mkDerivation rec {
     hash = "sha256-kWW9ID/eYZH0O/Ge8pf3Cso4yu644R5EiQFYfZMcizs=";
   };
 
+  configureFlags =
+    [
+      (lib.enableFeature enableSystemd "systemd")
+    ]
+    # implicit declaration of function 'rpl_malloc', ; did you mean 'realloc'
+    #
+    # It looks like in case of cross-compilation, autoconf assumes that malloc of the
+    # target platform is broken.
+    ++ lib.optionals (!lib.systems.equals stdenv.buildPlatform stdenv.hostPlatform) [
+      "ac_cv_func_malloc_0_nonnull=yes"
+      "ac_cv_func_realloc_0_nonnull=yes"
+    ];
+
   nativeBuildInputs = [
     autoreconfHook
     bison
     flex
   ];
-  buildInputs = [
-    pam
-    systemdLibs
-  ];
+  buildInputs =
+    [
+      pam
+    ]
+    ++ lib.optional enableSystemd systemdLibs
+    ++ lib.optional stdenv.hostPlatform.isMusl musl-fts;
 
   postPatch = ''
     substituteInPlace src/tools/Makefile.am \