diff -r c568b6ac5e89 configure.ac
--- a/configure.ac	Wed Dec 21 17:30:50 2016 +0100
+++ b/configure.ac	Wed Dec 21 22:04:16 2016 +0100
@@ -3386,7 +3386,7 @@
  futimens futimes gai_strerror getentropy \
  getgrouplist getgroups getlogin getloadavg getpeername getpgid getpid \
  getpriority getresuid getresgid getpwent getspnam getspent getsid getwd \
- initgroups kill killpg lchmod lchown lockf linkat lstat lutimes mmap \
+ initgroups kill killpg lchmod lchown linkat lstat lutimes mmap \
  memrchr mbrtowc mkdirat mkfifo \
  mkfifoat mknod mknodat mktime mremap nice openat pathconf pause pipe2 plock poll \
  posix_fallocate posix_fadvise pread \
@@ -3763,6 +3763,15 @@
   [AC_MSG_RESULT(no)
 ])
 
+# Issue #28762: lockf() is available on Android API level 24, but the F_LOCK
+# macro is not defined in android-ndk-r13.
+AC_MSG_CHECKING(for lockf)
+AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <unistd.h> ]],[[lockf(0, F_LOCK, 0);]])],
+  [AC_DEFINE(HAVE_LOCKF, 1, Define to 1 if you have the 'lockf' function and the F_LOCK macro.)
+   AC_MSG_RESULT(yes)],
+  [AC_MSG_RESULT(no)
+])
+
 # On OSF/1 V5.1, getaddrinfo is available, but a define
 # for [no]getaddrinfo in netdb.h.
 AC_MSG_CHECKING(for getaddrinfo)