diff --git a/pkgs/development/compilers/gcc/all.nix b/pkgs/development/compilers/gcc/all.nix
index ca95661e0d6e..444253a37878 100644
--- a/pkgs/development/compilers/gcc/all.nix
+++ b/pkgs/development/compilers/gcc/all.nix
@@ -24,6 +24,7 @@ let
         profiledCompiler = false;
         libcCross = if stdenv.targetPlatform != stdenv.buildPlatform then args.libcCross else null;
         threadsCross = if stdenv.targetPlatform != stdenv.buildPlatform then threadsCross else { };
+        isl = if stdenv.hostPlatform.isDarwin then null else isl_0_20;
         # do not allow version skew when cross-building gcc
         #
         # When `gcc` is cross-built (`build` != `target` && `host` == `target`)