diff --git a/pkgs/games/freedroidrpg/default.nix b/pkgs/games/freedroidrpg/default.nix
index 84fd9c154a24..dcec52a3fa6d 100644
--- a/pkgs/games/freedroidrpg/default.nix
+++ b/pkgs/games/freedroidrpg/default.nix
@@ -18,6 +18,9 @@ in stdenv.mkDerivation {
       url = "https://gitlab.com/freedroid/freedroid-src/-/commit/e610d427374226b79da5258d979936459f30c761.patch";
       sha256 = "1s7sw4dkc7b6i72j6x47driq6v0k3wss48l9ivd4fw40n3iaxjb1";
     })
+
+    # Do not embed build flags in the binary to reduce closure size.
+    ./drop-build-deps.patch
   ];
 
   nativeBuildInputs = [ pkg-config gettext python3 ];
diff --git a/pkgs/games/freedroidrpg/drop-build-deps.patch b/pkgs/games/freedroidrpg/drop-build-deps.patch
new file mode 100644
index 000000000000..d9f2d37b57c7
--- /dev/null
+++ b/pkgs/games/freedroidrpg/drop-build-deps.patch
@@ -0,0 +1,15 @@
+Do not embed paths to build-only depends (-I...SDL2-dev and friends)
+into savefile lua comments.
+--- a/src/savestruct_internal.c
++++ b/src/savestruct_internal.c
+@@ -486,8 +486,8 @@ void save_game_data(struct auto_string *strout)
+ 	autostr_append(strout,
+ 		"SAVEGAME: %s %s %s;sizeof(tux_t)=%d;sizeof(enemy)=%d;sizeof(bullet)=%d;MAXBULLETS=%d\n",
+ 		SAVEGAME_VERSION, SAVEGAME_REVISION, VERSION, (int)sizeof(tux_t), (int)sizeof(enemy), (int)sizeof(bullet), (int)MAXBULLETS);
+-	autostr_append(strout, "BUILD_CFLAGS: %s\n", BUILD_CFLAGS);
+-	autostr_append(strout, "BUILD_LDFLAGS: %s\n", BUILD_LDFLAGS);
++	autostr_append(strout, "BUILD_CFLAGS: %s\n", "<hidden>");
++	autostr_append(strout, "BUILD_LDFLAGS: %s\n", "<hidden>");
+ 	autostr_append(strout, "VERSION: %s\n", freedroid_version);
+ 	autostr_append(strout, "--]]\n");
+