netdata: add debug option

pkgs/tools/system/netdata/default.nix

@@ -6,6 +6,7 @@
 , withIpmi ? (!stdenv.isDarwin), freeipmi
 , withNetfilter ? (!stdenv.isDarwin), libmnl, libnetfilter_acct
 , withSsl ? true, openssl
+, withDebug ? false
 }:
 
 with stdenv.lib;
@@ -33,6 +34,8 @@ stdenv.mkDerivation rec {
     ./no-files-in-etc-and-var.patch
   ];
 
+  NIX_CFLAGS_COMPILE = optional withDebug "-O1 -ggdb -DNETDATA_INTERNAL_CHECKS=1";
+
   postInstall = optionalString (!stdenv.isDarwin) ''
     # rename this plugin so netdata will look for setuid wrapper
     mv $out/libexec/netdata/plugins.d/apps.plugin \