Create a new libsubid

Closes #154

Currently this has three functions: one which returns the
list of subuid ranges for a user, one returning the subgids,
and one which frees the ranges lists.

I might be mistaken about what -disable-man means;  some of
the code suggests it means just don't re-generate them, but
not totally ignore them.  But that doesn't seem to really work,
so let's just ignore man/ when -disable-man.

Remove --disable-shared.  I'm not sure why it was there, but it stems
from long, long ago, and I suspect it comes from some ancient
toolchain bug.

Create a tests/run_some, a shorter version of run_all.  I'll
slowly add tests to this as I verify they work, then I can
work on fixing the once which don't.

Also, don't touch man/ if not -enable-man.

Changelog:
	Apr 22: change the subid list api as recomended by Dan Walsh.
	Apr 23: implement get_subid_owner
	Apr 24: implement range add/release
	Apr 25: finish tests and rebase
	May 10: make @owner const

Signed-off-by: Serge Hallyn <serge@hallyn.com>

tests/libsubid/01_list_ranges/config/etc/subgid

@@ -0,0 +1,2 @@
+foo:200000:10000
+root:500000:1000

tests/libsubid/01_list_ranges/config/etc/subuid

@@ -0,0 +1,3 @@
+foo:300000:10000
+foo:400000:10000
+root:500000:1000

tests/libsubid/01_list_ranges/list_ranges.test

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+
+. ../../common/config.sh
+. ../../common/log.sh
+
+log_start "$0" "list_ranges shows subid ranges"
+
+save_config
+
+# restore the files on exit
+trap 'log_status "$0" "FAILURE"; restore_config' 0
+
+change_config
+
+echo -n "list foo's ranges..."
+${build_path}/src/list_subid_ranges foo > /tmp/subuidlistout
+${build_path}/src/list_subid_ranges -g foo > /tmp/subgidlistout
+echo "OK"
+
+echo -n "Check the subuid ranges..."
+[ $(wc -l /tmp/subuidlistout | awk '{ print $1 }') -eq 2 ]
+grep "0: foo 300000 10000" /tmp/subuidlistout
+grep "1: foo 400000 10000" /tmp/subuidlistout
+echo "OK"
+
+echo -n "Check the subgid ranges..."
+[ $(wc -l /tmp/subgidlistout | awk '{ print $1 }') -eq 1 ]
+grep "0: foo 200000 10000" /tmp/subgidlistout
+echo "OK"
+
+log_status "$0" "SUCCESS"
+restore_config
+trap '' 0
+