unix: add Major, Minor and Mkdev functions on Solaris

Add Major, Minor and Mkdev functions for converting device numbers to
their major/minor components and vice versa.

Use the respective functions provided by the Solaris libc instead of
reimplementing them.

Test the conversion function with some well-known static device numbers
for devices which should be present on any Solaris system.

Re-generated files on OpenIndiana Hipster 2017.04 (SunOS 5.11) which
also added some previously missing error constants.

Change-Id: Ief9ea973d91c24956571eb8fafc8a4525b0f5b90
Reviewed-on: https://go-review.googlesource.com/64390
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/mkerrors.sh

@@ -283,6 +283,7 @@ includes_SunOS='
 #include <sys/mman.h>
 #include <sys/wait.h>
 #include <sys/ioctl.h>
+#include <sys/mkdev.h>
 #include <net/bpf.h>
 #include <net/if.h>
 #include <net/if_arp.h>
@@ -347,6 +348,7 @@ ccflags="$@"
 		$2 !~ /^EXPR_/ &&
 		$2 ~ /^E[A-Z0-9_]+$/ ||
 		$2 ~ /^B[0-9_]+$/ ||
+		$2 ~ /^(OLD|NEW)DEV$/ ||
 		$2 == "BOTHER" ||
 		$2 ~ /^CI?BAUD(EX)?$/ ||
 		$2 == "IBSHIFT" ||