yosys: 0.55 -> 0.60

diff --git a/tests/cxxrtl/run-test.sh b/tests/cxxrtl/run-test.sh

index ee299fc82..595cd3f88 100755

--- a/tests/cxxrtl/run-test.sh

+++ b/tests/cxxrtl/run-test.sh

@@ -5,7 +5,7 @@ set -ex

 run_subtest () {

     local subtest=$1; shift

-    ${CC:-gcc} -std=c++11 -O2 -o cxxrtl-test-${subtest} -I../../backends/cxxrtl/runtime test_${subtest}.cc -lstdc++

+    ${CXX:-gcc} -std=c++11 -O2 -o cxxrtl-test-${subtest} -I../../backends/cxxrtl/runtime test_${subtest}.cc -lstdc++

     ./cxxrtl-test-${subtest}

 }

@@ -14,4 +14,4 @@ run_subtest value_fuzz

 # Compile-only test.

 ../../yosys -p "read_verilog test_unconnected_output.v; select =*; proc; clean; write_cxxrtl cxxrtl-test-unconnected_output.cc"

-${CC:-gcc} -std=c++11 -c -o cxxrtl-test-unconnected_output -I../../backends/cxxrtl/runtime cxxrtl-test-unconnected_output.cc

+${CXX:-gcc} -std=c++11 -c -o cxxrtl-test-unconnected_output -I../../backends/cxxrtl/runtime cxxrtl-test-unconnected_output.cc

diff --git a/tests/fmt/run-test.sh b/tests/fmt/run-test.sh

index 998047f83..2a4a59f01 100644

--- a/tests/fmt/run-test.sh

+++ b/tests/fmt/run-test.sh

@@ -51,7 +51,7 @@ test_cxxrtl () {

 	local subtest=$1; shift

 	../../yosys -p "read_verilog ${subtest}.v; proc; clean; write_cxxrtl -print-output std::cerr yosys-${subtest}.cc"

-	${CC:-gcc} -std=c++11 -o yosys-${subtest} -I../../backends/cxxrtl/runtime ${subtest}_tb.cc -lstdc++

+	${CXX:-gcc} -std=c++11 -o yosys-${subtest} -I../../backends/cxxrtl/runtime ${subtest}_tb.cc -lstdc++

 	./yosys-${subtest} 2>yosys-${subtest}.log

 	iverilog -o iverilog-${subtest} ${subtest}.v ${subtest}_tb.v

 	./iverilog-${subtest} |grep -v '\$finish called' >iverilog-${subtest}.log

@@ -69,7 +69,7 @@ diff iverilog-always_full.log iverilog-always_full-1.log

 ../../yosys -p "read_verilog display_lm.v" >yosys-display_lm.log

 ../../yosys -p "read_verilog display_lm.v; write_cxxrtl yosys-display_lm.cc"

-${CC:-gcc} -std=c++11 -o yosys-display_lm_cc -I../../backends/cxxrtl/runtime display_lm_tb.cc -lstdc++

+${CXX:-gcc} -std=c++11 -o yosys-display_lm_cc -I../../backends/cxxrtl/runtime display_lm_tb.cc -lstdc++

 ./yosys-display_lm_cc >yosys-display_lm_cc.log

 for log in yosys-display_lm.log yosys-display_lm_cc.log; do

 	grep "^%l: \\\\bot\$" "$log"

  lib,

  stdenv,

  fetchFromGitHub,

  fetchpatch2,

  # nativeBuildInputs

  bison,

in

stdenv.mkDerivation (finalAttrs: {

  pname = "yosys";

  version = "0.55";

  version = "0.60";

  src = fetchFromGitHub {

    owner = "YosysHQ";

    repo = "yosys";

    tag = "v${finalAttrs.version}";

    hash = "sha256-GddNbAtH5SPm7KTa5kCm/vGq4xOczx+jCnOSQl55gUI=";

    hash = "sha256-BVrSq9nWbdu/PIXfwLW7ZkHTz6SrmsqJMSkVa6CsBm8=";

    fetchSubmodules = true;

    leaveDotGit = true;

    postFetch = ''

    (python3.withPackages (

      pp: with pp; [

        click

        cxxheaderparser

        pybind11

      ]

    ))

  ]

  makeFlags = [ "PREFIX=${placeholder "out"}" ];

  patches = [

    # Backport fix amaranth code compilation

    # TODO remove when updating to 0.56

    # https://github.com/YosysHQ/yosys/pull/5182

    (fetchpatch2 {

      name = "treat-zero-width-constant-as-zero.patch";

      url = "https://github.com/YosysHQ/yosys/commit/478b6a2b3fbab0fd4097b841914cbe8bb9f67268.patch";

      hash = "sha256-KeLoZfkXMk2KIPN9XBQdqWqohywQONlWUIvrGwgphKs=";

    })

    ./plugin-search-dirs.patch

    ./fix-clang-build.patch

  ];

  postPatch = ''

    substituteInPlace ./Makefile \

      --replace-fail 'echo UNKNOWN' 'echo ${builtins.substring 0 10 finalAttrs.src.rev}'

    fi

  ''

  + lib.optionalString enablePython ''

    echo "PYOSYS_USE_UV := 0" >> Makefile.conf

    echo "ENABLE_PYOSYS := 1" >> Makefile.conf

    echo "PYTHON_DESTDIR := $out/${python3.sitePackages}" >> Makefile.conf

    echo "BOOST_PYTHON_LIB := -lboost_python${lib.versions.major python3.version}${lib.versions.minor python3.version}" >> Makefile.conf

diff --git i/passes/cmds/plugin.cc w/passes/cmds/plugin.cc

index 08b4aa8c4..f00f540e9 100644

--- i/passes/cmds/plugin.cc

+++ w/passes/cmds/plugin.cc

@@ -87,15 +87,33 @@ void load_plugin(std::string filename, std::vector<std::string> aliases)

 			// We were unable to open the file, try to do so from the plugin directory

 			if (hdl == NULL && orig_filename.find('/') == std::string::npos) {

-				hdl = dlopen([orig_filename]() {

-					std::string new_path = proc_share_dirname() + "plugins/" + orig_filename;

+                            std::string install_dir = proc_share_dirname() + "plugins";

-					// Check if we need to append .so

-					if (new_path.find(".so") == std::string::npos)

-						new_path.append(".so");

+				vector<string> all_dirs;

+				all_dirs.push_back(install_dir);

-					return new_path;

-				}().c_str(), RTLD_LAZY|RTLD_LOCAL);

+				char* plugin_dirs = getenv("NIX_YOSYS_PLUGIN_DIRS");

+				if (plugin_dirs != NULL) {

+					std::string p(plugin_dirs), t;

+					std::stringstream ss(p);

+

+					while(std::getline(ss, t, ':')) {

+						all_dirs.push_back(t);

+					}

+				}

+

+				for (auto dir : all_dirs) {

+					hdl = dlopen([dir, orig_filename]() {

+						std::string new_path = dir + "/" + orig_filename;

+

+						// Check if we need to append .so

+						if (new_path.find(".so") == std::string::npos)

+							new_path.append(".so");

+

+						return new_path;

+					}().c_str(), RTLD_LAZY|RTLD_LOCAL);

+					if (hdl != NULL) break;

+                                }

 			}

 			if (hdl == NULL)