{pkgs ? import <nixpkgs> {}}:
pkgs.stdenv.mkDerivation {
  name = "riverguile";
  src = pkgs.fetchgit {
    url = "https://git.sr.ht/~leon_plickat/riverguile/";
    rev = "744ce4b1eb5950d0dc795d64bfac6b7738eec6f1";
    hash = "sha256-80XVaq+17Vu+DAs7pjt3cu5wiK37680A7S6qIulPRLc=";
  };
  patches = [
    (pkgs.writeText "nix-build.patch" ''
diff --git a/Makefile b/Makefile
index 915f7ac..ff2b3c2 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 SCANNER := wayland-scanner
 
-PREFIX=/usr/local
+PREFIX=''${out}
 BINDIR=$(PREFIX)/bin
 DATADIR=$(PREFIX)/share
 MODULEDIR=$(DATADIR)/guile/3.0
diff --git a/src/call-idle-handler.c b/src/call-idle-handler.c
index 727656e..b4d4474 100644
--- a/src/call-idle-handler.c
+++ b/src/call-idle-handler.c
@@ -8,7 +8,7 @@ static void *call_idle_handler_inner (void *data)
 	struct Call_idle_handler_parameters *params =
 		(struct Call_idle_handler_parameters *)data;
 
-	SCM event;
+	SCM event = { 0 };
 	switch (params->event)
 	{
 		case IDLE:   event = scm_from_utf8_symbol("idle");   break;
'')
  ];
  buildInputs = with pkgs; [wayland-scanner wayland guile];
  nativeBuildInputs = [pkgs.pkg-config];
}