gdb: Fix safe path for cross

pkgs/development/tools/misc/gdb/default.nix

@@ -1,4 +1,4 @@
-{ stdenv
+{ stdenv, targetPackages
 
 # Build time
 , fetchurl, pkgconfig, perl, texinfo, setupDebugInfoDirs, buildPackages
@@ -8,9 +8,12 @@
 
 , pythonSupport ? stdenv.hostPlatform == stdenv.buildPlatform && !stdenv.hostPlatform.isCygwin, python3 ? null
 , guile ? null
-# $debugdir:$datadir/auto-load are whitelisted by default by GDB
-, safePaths ? [ "$debugdir" "$datadir/auto-load" stdenv.cc.cc.lib ]
-
+, safePaths ? [
+   # $debugdir:$datadir/auto-load are whitelisted by default by GDB
+   "$debugdir" "$datadir/auto-load"
+   # targetPackages so we get the right libc when cross-compiling and using buildPackages.gdb
+   targetPackages.stdenv.cc.cc.lib
+  ]
 }:
 
 let