diff --git a/pkgs/servers/gpm/default.nix b/pkgs/servers/gpm/default.nix
index 85bb78fcb89b..9a83d607c4c3 100644
--- a/pkgs/servers/gpm/default.nix
+++ b/pkgs/servers/gpm/default.nix
@@ -64,6 +64,9 @@ stdenv.mkDerivation {
     "--sysconfdir=/etc"
     "--localstatedir=/var"
     (if withNcurses then "--with-curses" else "--without-curses")
+    # The code won't compile in c23 mode.
+    # https://gcc.gnu.org/gcc-15/porting_to.html#c23-fn-decls-without-parameters
+    "CFLAGS=-std=gnu17"
   ];
 
   enableParallelBuilding = true;