Add futimes, futimesat, and lutimes.

Spotted these while cleaning up <sys/cdefs.h> --- if we remove __USE_XOPEN2K8,
libchrome decides you "must" have futimes. Adding the missing functions (all
just alternative interfaces to utimensat(2) system call) lets us clean up
without breaking anything.

Change-Id: If44fab08ee3de0e31066d650d128a3c96323529b
diff --git a/libc/Android.bp b/libc/Android.bp
index 4a44fc6..ba62592 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1373,6 +1373,7 @@
         "bionic/syslog.cpp",
         "bionic/sys_siglist.c",
         "bionic/sys_signame.c",
+        "bionic/sys_time.cpp",
         "bionic/system_properties.cpp",
         "bionic/tdestroy.cpp",
         "bionic/termios.cpp",
@@ -1380,7 +1381,6 @@
         "bionic/tmpfile.cpp",
         "bionic/umount.cpp",
         "bionic/unlink.cpp",
-        "bionic/utimes.cpp",
         "bionic/wait.cpp",
         "bionic/wchar.cpp",
         "bionic/wctype.cpp",