diff --git a/pkgs/by-name/ma/mailsend/package.nix b/pkgs/by-name/ma/mailsend/package.nix
index de46e1ea1214..a3f2c59ebf52 100644
--- a/pkgs/by-name/ma/mailsend/package.nix
+++ b/pkgs/by-name/ma/mailsend/package.nix
@@ -36,6 +36,8 @@ stdenv.mkDerivation rec {
     })
   ];
 
+  NIX_CFLAGS_COMPILE = "-Wno-error=implicit-function-declaration";
+
   enableParallelBuilding = true;
 
   meta = with lib; {