feat: add C & Zig bindings for unix acceptor and connector

build.zig

@@ -59,6 +59,7 @@ pub fn build(b: *std.Build) void {
         "src/c/metronome.cpp",
         "src/c/signal.cpp",
         "src/c/timeout.cpp",
+        "src/c/unx.cpp",
         "src/c/trace.cpp",
         "src/cbor.cpp",
         "src/executor_asio.cpp",
@@ -122,6 +123,7 @@ pub fn build(b: *std.Build) void {
         "test/spawn_exit.cpp",
         "test/tests.cpp",
         "test/timeout_test.cpp",
+        "test/unx_c_api.cpp",
     }, .flags = &cppflags });
     tests.linkLibrary(lib);
     tests.linkLibrary(asio_dep.artifact("asio"));