diff --git a/pkgs/servers/sql/mysql/5.5.x.nix b/pkgs/servers/sql/mysql/5.5.x.nix
index 5a747fb85abd..29d25b77afc8 100644
--- a/pkgs/servers/sql/mysql/5.5.x.nix
+++ b/pkgs/servers/sql/mysql/5.5.x.nix
@@ -49,6 +49,7 @@ self = stdenv.mkDerivation rec {
     "-DINSTALL_SHAREDIR=share/mysql"
   ];
 
+  NIX_CFLAGS_COMPILE = [ "-fpermissive" ]; # since gcc-7
   NIX_LDFLAGS = stdenv.lib.optionalString stdenv.isLinux "-lgcc_s";
 
   prePatch = ''