mini-httpd: fix the build

Moved back to C++14 where dynamic exception specifications are
deprecated but still present.

ZHF: #172160

pkgs/servers/http/mini-httpd/default.nix

@@ -13,6 +13,8 @@ stdenv.mkDerivation rec {
 
   enableParallelBuilding = true;
 
+  NIX_CFLAGS_COMPILE = [ "-std=c++14" ];
+
   meta = {
     homepage = "http://mini-httpd.nongnu.org/";
     description = "minimalistic high-performance web server";