2 files changed, 2 insertions, 2 deletions
diff --git a/pkgs/development/libraries/zeroc-ice/3.6.nix b/pkgs/development/libraries/zeroc-ice/3.6.nix
index 896973e32eb..725af51487c 100644
--- a/pkgs/development/libraries/zeroc-ice/3.6.nix
+++ b/pkgs/development/libraries/zeroc-ice/3.6.nix
@@ -21,7 +21,7 @@ stdenv.mkDerivation rec {
     sourceRoot=$sourceRoot/cpp
   '';
 
-  prePatch = lib.optional stdenv.isDarwin ''
+  prePatch = lib.optionalString stdenv.isDarwin ''
     substituteInPlace config/Make.rules.Darwin \
         --replace xcrun ""
   '';
diff --git a/pkgs/development/libraries/zeroc-ice/default.nix b/pkgs/development/libraries/zeroc-ice/default.nix
index ef16e381bcf..f522c181039 100644
--- a/pkgs/development/libraries/zeroc-ice/default.nix
+++ b/pkgs/development/libraries/zeroc-ice/default.nix
@@ -35,7 +35,7 @@ in stdenv.mkDerivation rec {
 
   NIX_CFLAGS_COMPILE = "-Wno-error=class-memaccess -Wno-error=deprecated-copy";
 
-  prePatch = lib.optional stdenv.isDarwin ''
+  prePatch = lib.optionalString stdenv.isDarwin ''
     substituteInPlace Make.rules.Darwin \
         --replace xcrun ""
   '';