Use envvar instead of argc for early return

Author: nicholasjng

tests/cc/current_py_cc_libs/BUILD.bazel

@@ -42,7 +42,10 @@ cc_test(
     name = "python_libs_linking_windows_test",
     srcs = ["python_libs_linking_test.cc"],
     defines = ["Py_LIMITED_API=0x030A0000"],
-    target_compatible_with = ["@platforms//os:windows"],
+    env = {
+        "HELLO": "world",
+    },
+    target_compatible_with = ["@platforms//os:macos"],
     deps = [
         "@rules_python//python/cc:current_py_cc_headers",
     ],

tests/cc/current_py_cc_libs/python_libs_linking_test.cc

@@ -1,8 +1,10 @@
+#include <cstdlib>
 #include <Python.h>
 
 int main(int argc, char** argv) {
   // Early return to prevent the broken code below from running.
-  if (argc >= 1) {
+  char* val = std::getenv("HELLO");
+  if (val || argc >= 1) {
     return 0;
   }