library: rework namespace calls

Functions related to namespaces were half-in half-out of the
procps library and didn't fit the standard naming scheme.

While struct { long ns[x]} is a bit clunky, its the only way
to "lock in" x. The alternative is to use ns_* variables.

This work was needed before pgrep could be converted.

lib/nsutils.c

@@ -1,30 +0,0 @@
-#include <stdio.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#include "proc/readproc.h"
-#include "nsutils.h"
-
-/* we need to fill in only namespace information */
-int ns_read(pid_t pid, proc_t *ns_task)
-{
-	struct stat st;
-	char buff[50];
-	int i, rc = 0;
-
-	for (i = 0; i < NUM_NS; i++) {
-		snprintf(buff, sizeof(buff), "/proc/%i/ns/%s", pid,
-			get_ns_name(i));
-		if (stat(buff, &st)) {
-			if (errno != ENOENT)
-				rc = errno;
-			ns_task->ns[i] = 0;
-			continue;
-		}
-		ns_task->ns[i] = st.st_ino;
-	}
-	return rc;
-}

lib/test_nsutils.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-
-#include "nsutils.h"
-
-const char *get_ns_name(int id)
-{
-	return NULL;
-}
-
-int main(int argc, char *argv[])
-{
-	printf("Hello, World!\n");
-	return EXIT_SUCCESS;
-}