uwsgi: the php 8.x library is just libphp.so, not libphp8

patch taken from the archlinux PKGBUILD
dc8835dbc3/trunk/PKGBUILD (L106)

pkgs/servers/uwsgi/default.nix

@@ -91,12 +91,15 @@ stdenv.mkDerivation rec {
     inherit python2 python3;
   };
 
+  php8 = builtins.head (builtins.splitVersion php.version) == "8";
+  php8_no_version = ''sed -e "s/ + php_version//" -i plugins/php/uwsgiplugin.py'';
+
   postPatch = ''
     for f in uwsgiconfig.py plugins/*/uwsgiplugin.py; do
       substituteInPlace "$f" \
         --replace pkg-config "$PKG_CONFIG"
     done
-  '';
+  '' + (lib.optionalString php8 php8_no_version);
 
   configurePhase = ''
     export pluginDir=$out/lib/uwsgi