diff --git a/pkgs/tools/networking/ncftp/default.nix b/pkgs/tools/networking/ncftp/default.nix
index 02dd29c0fda5..c31e6333b684 100644
--- a/pkgs/tools/networking/ncftp/default.nix
+++ b/pkgs/tools/networking/ncftp/default.nix
@@ -17,7 +17,12 @@ stdenv.mkDerivation rec {
   # gcc-10. Otherwise build fails as:
   #   ld: bookmark.o: (.bss+0x20): multiple definition of `gBm';
   #     gpshare.o:(.bss+0x0): first defined here
-  env.NIX_CFLAGS_COMPILE = "-fcommon";
+  env.NIX_CFLAGS_COMPILE = toString ([ "-fcommon" ]
+    # these are required for the configure script to work with clang
+    ++ lib.optionals stdenv.isDarwin [
+      "-Wno-implicit-int"
+      "-Wno-implicit-function-declaration"
+    ]);
 
   preConfigure = ''
     find -name Makefile.in | xargs sed -i '/^TMPDIR=/d'