diff --git a/libcutils/include/cutils/threads.h b/libcutils/include/cutils/threads.h
index 18861840e..92564b8db 100644
--- a/libcutils/include/cutils/threads.h
+++ b/libcutils/include/cutils/threads.h
@@ -23,18 +23,3 @@
 #else
 #include <pthread.h>
 #endif
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-//
-// Deprecated: use android::base::GetThreadId instead, which doesn't truncate on Mac/Windows.
-//
-#if !defined(__GLIBC__) || __GLIBC__ >= 2 && __GLIBC_MINOR__ < 30
-extern pid_t gettid();
-#endif
-
-#ifdef __cplusplus
-}
-#endif
diff --git a/libcutils/threads.cpp b/libcutils/threads.cpp
index 263872084..cca50c191 100644
--- a/libcutils/threads.cpp
+++ b/libcutils/threads.cpp
@@ -14,11 +14,13 @@
 ** limitations under the License.
 */
 
-#include <cutils/threads.h>
+#include <sys/types.h>
 
 #if defined(__APPLE__)
+#include <pthread.h>
 #include <stdint.h>
 #elif defined(__linux__)
+#include <pthread.h>
 #include <syscall.h>
 #include <unistd.h>
 #elif defined(_WIN32)
@@ -29,7 +31,7 @@
 // No definition needed for Android because we'll just pick up bionic's copy.
 // No definition needed for Glibc >= 2.30 because it exposes its own copy.
 #else
-pid_t gettid() {
+extern "C" pid_t gettid() {
 #if defined(__APPLE__)
   uint64_t tid;
   pthread_threadid_np(NULL, &tid);