Implement the GNU basename(3) in addition to the POSIX one.

Code like perf(1) needs this.

Bug: 11860789
Change-Id: I907eb448052a7b165e4012d74303330d32328cb2
diff --git a/libc/Android.mk b/libc/Android.mk
index ca22bbc..937f741 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -122,6 +122,7 @@
     bionic/getpgrp.cpp \
     bionic/getpid.cpp \
     bionic/gettid.cpp \
+    bionic/__gnu_basename.cpp \
     bionic/inotify_init.cpp \
     bionic/lchown.cpp \
     bionic/lfs64_support.cpp \