gethostname.c: change to report ENAMETOOLONG error when buflen is less

change to behaviour the same as glibc for the check about buflen

Change-Id: I98265a8fe441df6fed2527686f89b087364ca53d
Signed-off-by: Yongqin Liu <yongqin.liu@linaro.org>
diff --git a/libc/Android.mk b/libc/Android.mk
index 893738a..345a1f3 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -43,7 +43,6 @@
     bionic/ether_aton.c \
     bionic/ether_ntoa.c \
     bionic/fts.c \
-    bionic/gethostname.c \
     bionic/getpriority.c \
     bionic/if_indextoname.c \
     bionic/if_nametoindex.c \
@@ -120,6 +119,7 @@
     bionic/getauxval.cpp \
     bionic/getcwd.cpp \
     bionic/getentropy_linux.c \
+    bionic/gethostname.cpp \
     bionic/getpgrp.cpp \
     bionic/getpid.cpp \
     bionic/gettid.cpp \