Disable fuzztest subprocess library on Android.

In Chromium, we build against an older version of the Android NDK for compatibility with older Android devices. That version seems to lack the posix_spawnp APIs that are required by FuzzTest's subprocess library.

Disable the subprocess library on such systems.

PiperOrigin-RevId: 577169201

fuzztest/internal/subprocess.cc

@@ -40,7 +40,8 @@
 
 namespace fuzztest::internal {
 
-#if !defined(_MSC_VER)
+#if !defined(_MSC_VER) && !(defined(__ANDROID_MIN_SDK_VERSION__) && \
+                            __ANDROID_MIN_SDK_VERSION__ < 28)
 
 TerminationStatus::TerminationStatus(int status) : status_(status) {}
 
@@ -288,7 +289,8 @@ RunResults SubProcess::Run(
   return {TerminationStatus(status.get()), stdout_output, stderr_output};
 }
 
-#endif  // !defined(_MSC_VER)
+#endif  // !defined(_MSC_VER) && !(defined(__ANDROID_MIN_SDK_VERSION__) &&
+        // __ANDROID_MIN_SDK_VERSION__ < 28)
 
 RunResults RunCommand(
     const std::vector<std::string>& command_line,
@@ -297,6 +299,10 @@ RunResults RunCommand(
 #if defined(_MSC_VER)
   FUZZTEST_INTERNAL_CHECK(false,
                           "Subprocess library not implemented on Windows yet.");
+#elif defined(__ANDROID_MIN_SDK_VERSION__) && __ANDROID_MIN_SDK_VERSION__ < 28
+  FUZZTEST_INTERNAL_CHECK(
+      false,
+      "Subprocess library not implemented on older Android NDK versions yet");
 #else
   SubProcess proc;
   return proc.Run(command_line, environment, timeout);