diff --git a/pkgs/by-name/ra/ratpoison/package.nix b/pkgs/by-name/ra/ratpoison/package.nix
index 58916d67cf6f..96e0e17305dc 100644
--- a/pkgs/by-name/ra/ratpoison/package.nix
+++ b/pkgs/by-name/ra/ratpoison/package.nix
@@ -59,6 +59,12 @@ stdenv.mkDerivation (finalAttrs: {
 
   strictDeps = true;
 
+  postPatch = lib.optionalString stdenv.hostPlatform.isDarwin ''
+    substituteInPlace src/getopt.h \
+      --replace-fail "extern int getopt ();" \
+                     "extern int getopt (int argc, char *const *argv, const char *shortopts);"
+  '';
+
   configureFlags = [
     # >=1.4.9 requires this even with readline in inputs
     "--enable-history"