downgrade glibc to 2.19 and update README

test/go/BUILD

@@ -1,21 +0,0 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_binary", "go_library")
-
-# go build -ldflags "-linkmode external -extldflags -static" hello.go
-go_library(
-    name = "go_lib",
-    srcs = ["hello.go"],
-    cgo = True,
-    importpath = "github.com/motiejus/bazel-zig-cc/test/go",
-    visibility = ["//visibility:private"],
-    target_compatible_with = select({
-        "@platforms//os:linux": ["@com_github_ziglang_zig//:musl"],
-        "//conditions:default": [],
-    }),
-)
-
-go_binary(
-    name = "go",
-    embed = [":go_lib"],
-    visibility = ["//visibility:public"],
-    static = "on",
-)

test/go/hello.go

@@ -1,9 +0,0 @@
-package main
-
-// #include <stdio.h>
-// void helloworld() { printf("hello, world\n"); }
-import "C"
-
-func main() {
-	C.helloworld()
-}