+#if defined(__has_feature)
+#if __has_feature(thread_sanitizer)
+#define MONO_HAS_CLANG_THREAD_SANITIZER 1
+#else
+#define MONO_HAS_CLANG_THREAD_SANITIZER 0
+#endif
+#else
+#define MONO_HAS_CLANG_THREAD_SANITIZER 0
+#endif
+
+/* Used to tell Clang's ThreadSanitizer to not report data races that occur within a certain function */
+#if MONO_HAS_CLANG_THREAD_SANITIZER
+#define MONO_NO_SANITIZE_THREAD __attribute__ ((no_sanitize("thread")))
+#else
+#define MONO_NO_SANITIZE_THREAD
+#endif
+
+/* Used when building with Android NDK's unified headers */
+#if defined(HOST_ANDROID) && defined (ANDROID_UNIFIED_HEADERS)
+#if __ANDROID_API__ < 21
+
+typedef int32_t __mono_off32_t;
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#if !defined(mmap)
+/* Unified headers before API 21 do not declare mmap when LARGE_FILES are used (via -D_FILE_OFFSET_BITS=64)
+ * which is always the case when Mono build targets Android. The problem here is that the unified headers
+ * map `mmap` to `mmap64` if large files are enabled but this api exists only in API21 onwards. Therefore
+ * we must carefully declare the 32-bit mmap here without changing the ABI along the way. Carefully because
+ * in this instance off_t is redeclared to be 64-bit and that's not what we want.
+ */
+void* mmap (void*, size_t, int, int, int, __mono_off32_t);
+#endif /* !mmap */
+
+#ifdef HAVE_SYS_SENDFILE_H
+#include <sys/sendfile.h>
+#endif
+
+#if !defined(sendfile)
+/* The same thing as with mmap happens with sendfile */
+ssize_t sendfile (int out_fd, int in_fd, __mono_off32_t* offset, size_t count);
+#endif /* !sendfile */
+
+#endif /* __ANDROID_API__ < 21 */
+#endif /* HOST_ANDROID && ANDROID_UNIFIED_HEADERS */
+