build: check for sys/sysmacros.h in configure

We now need this header to build the core library.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

configure.ac

@@ -81,6 +81,7 @@ AC_CHECK_FUNC([ppoll], [], [FUNC_NOT_FOUND_LIB([ppoll])])
 AC_CHECK_HEADERS([getopt.h], [], [HEADER_NOT_FOUND_LIB([getopt.h])])
 AC_CHECK_HEADERS([dirent.h], [], [HEADER_NOT_FOUND_LIB([dirent.h])])
 AC_CHECK_HEADERS([sys/poll.h], [], [HEADER_NOT_FOUND_LIB([sys/poll.h])])
+AC_CHECK_HEADERS([sys/sysmacros.h], [], [HEADER_NOT_FOUND_LIB([sys/sysmacros.h])])
 AC_CHECK_HEADERS([linux/gpio.h], [], [HEADER_NOT_FOUND_LIB([linux/gpio.h])])
 
 AC_ARG_ENABLE([tools],