Add C11 timespec_get.

Bug: https://github.com/android-ndk/ndk/issues/744
Test: ran tests
Change-Id: Iad9514946e06d55b6a3aa0f945d9a63bff900881
diff --git a/libc/Android.bp b/libc/Android.bp
index 212a1b1..4fc3484 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1389,6 +1389,7 @@
         "bionic/tdestroy.cpp",
         "bionic/termios.cpp",
         "bionic/thread_private.cpp",
+        "bionic/timespec_get.cpp",
         "bionic/tmpfile.cpp",
         "bionic/umount.cpp",
         "bionic/unlink.cpp",