downgrade glibc to 2.19 and update README

test/c/BUILD

@@ -1,13 +0,0 @@
-cc_binary(
-    name = "hello",
-    srcs = ["hello.cpp"],
-    target_compatible_with = select({
-        "@platforms//os:linux": ["@com_github_ziglang_zig//:musl"],
-        "//conditions:default": [],
-    }),
-)
-
-cc_binary(
-    name = "exception",
-    srcs = ["exception.cpp"],
-)

test/c/exception.cpp

@@ -1,12 +0,0 @@
-#include <iostream>
-
-int main() {
-  std::cerr << "will throw and expect to catch an error..." << std::endl;
-
-  try {
-    throw "error";
-  } catch (const char* msg) {
-    std::cerr << "caught: " << msg << std::endl;
-  }
-  std::cerr << "done" << std::endl;
-}

test/c/hello.cpp

@@ -1,5 +0,0 @@
-#include <iostream>
-
-int main() {
-    std::cout << "Hello World!" << std::endl;
-}