Add O_PATH support for flistxattr()

A continuation of commit 2825f10b7f61558c264231a536cf3affc0d84204.

Add O_PATH compatibility support for flistxattr(). This allows
a process to list out all the extended attributes associated with
O_PATH file descriptors.

Change-Id: Ie2285ac7ad2e4eac427ddba6c2d182d41b130f75
diff --git a/libc/Android.mk b/libc/Android.mk
index 620f438..868d159 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -130,6 +130,7 @@
     bionic/fchmodat.cpp \
     bionic/ffs.cpp \
     bionic/fgetxattr.cpp \
+    bionic/flistxattr.cpp \
     bionic/flockfile.cpp \
     bionic/fpclassify.cpp \
     bionic/fsetxattr.cpp \