leveldb: fix static building

1. The Makefile is long gone and the patch in not needed anymore.

2. For some reason LEVELDB_BUILD_BENCHMARKS=OFF is necessary
   when building statically. (Note: this has always been of
   for the shared build)

pkgs/development/libraries/leveldb/default.nix

@@ -38,13 +38,9 @@ stdenv.mkDerivation rec {
     "-DBUILD_SHARED_LIBS=${if static then "OFF" else "ON"}"
     "-DCMAKE_SKIP_BUILD_RPATH=OFF"
     "-DLEVELDB_BUILD_TESTS=OFF"
+    "-DLEVELDB_BUILD_BENCHMARKS=OFF"
   ];
 
-  postPatch = lib.optionalString stdenv.hostPlatform.isStatic ''
-    # remove shared objects from "all" target
-    sed -i '/^all:/ s/$(SHARED_LIBS) $(SHARED_PROGRAMS)//' Makefile
-  '';
-
   postInstall = ''
     substituteInPlace "$out"/lib/cmake/leveldb/leveldbTargets.cmake \
       --replace 'INTERFACE_INCLUDE_DIRECTORIES "''${_IMPORT_PREFIX}/include"' 'INTERFACE_INCLUDE_DIRECTORIES "'$dev'"'