Trivial: Add missing AC_CHECK_HEADERS (#2610)
Fix warnings running bootstrap.sh for the following by adding missing
entries in configure.ac:
```
configure.ac: warning: missing AC_CHECK_HEADERS([stdint.h]) wanted by: lib/rb/ext/binary_protocol_accelerated.c:22
configure.ac: warning: missing AC_CHECK_HEADERS([strings.h]) wanted by: lib/cpp/src/thrift/transport/TFileTransport.cpp:39
```
Sort all of the AC_CHECK_HEADERS lines, for easier readability in configure.ac
diff --git a/configure.ac b/configure.ac
index 60b2489..de64936 100755
--- a/configure.ac
+++ b/configure.ac
@@ -591,30 +591,32 @@
AC_HEADER_SYS_WAIT
AC_TYPE_SIGNAL
AC_CHECK_HEADERS([arpa/inet.h])
-AC_CHECK_HEADERS([sys/param.h])
AC_CHECK_HEADERS([fcntl.h])
AC_CHECK_HEADERS([inttypes.h])
+AC_CHECK_HEADERS([libintl.h])
AC_CHECK_HEADERS([limits.h])
+AC_CHECK_HEADERS([malloc.h])
AC_CHECK_HEADERS([netdb.h])
AC_CHECK_HEADERS([netinet/in.h])
+AC_CHECK_HEADERS([openssl/rand.h])
+AC_CHECK_HEADERS([openssl/ssl.h])
+AC_CHECK_HEADERS([openssl/x509v3.h])
+AC_CHECK_HEADERS([poll.h])
AC_CHECK_HEADERS([pthread.h])
+AC_CHECK_HEADERS([sched.h])
AC_CHECK_HEADERS([signal.h])
AC_CHECK_HEADERS([stddef.h])
+AC_CHECK_HEADERS([stdint.h])
AC_CHECK_HEADERS([stdlib.h])
+AC_CHECK_HEADERS([strings.h])
AC_CHECK_HEADERS([sys/ioctl.h])
+AC_CHECK_HEADERS([sys/param.h])
+AC_CHECK_HEADERS([sys/poll.h])
+AC_CHECK_HEADERS([sys/resource.h])
AC_CHECK_HEADERS([sys/socket.h])
AC_CHECK_HEADERS([sys/time.h])
AC_CHECK_HEADERS([sys/un.h])
-AC_CHECK_HEADERS([poll.h])
-AC_CHECK_HEADERS([sys/poll.h])
-AC_CHECK_HEADERS([sys/resource.h])
AC_CHECK_HEADERS([unistd.h])
-AC_CHECK_HEADERS([libintl.h])
-AC_CHECK_HEADERS([malloc.h])
-AC_CHECK_HEADERS([openssl/ssl.h])
-AC_CHECK_HEADERS([openssl/rand.h])
-AC_CHECK_HEADERS([openssl/x509v3.h])
-AC_CHECK_HEADERS([sched.h])
AC_CHECK_HEADERS([wchar.h])
AC_CHECK_LIB(pthread, pthread_create)