build: Use AC_HEADER_MAJOR to find device macros

Depending on the OS/libc, device macros are defined in different
headers. This change ensures we include the right one.

sys/types.h - BSD
sys/mkdev.h - Sun
sys/sysmacros.h - glibc (Linux)

glibc currently pulls sys/sysmacros.h into sys/types.h, but this may
change in a future release.

https://sourceware.org/ml/libc-alpha/2015-11/msg00253.html

configure.ac

@@ -388,7 +388,8 @@ fi
 
 # Check for functions and headers.
 AC_CHECK_FUNCS(posix_memalign memalign getextmntent)
-AC_CHECK_HEADERS(sys/param.h sys/mount.h sys/mnttab.h sys/mkdev.h limits.h)
+AC_CHECK_HEADERS(sys/param.h sys/mount.h sys/mnttab.h limits.h)
+AC_HEADER_MAJOR
 
 AC_CHECK_MEMBERS([struct statfs.f_fstypename],,,[$ac_includes_default
 #include <sys/param.h>