add uname, thanks hiltjo

uname.c

@@ -0,0 +1,58 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/utsname.h>
+#include "util.h"
+
+int
+main(int argc, char *argv[])
+{
+	bool mflag = false;
+	bool nflag = false;
+	bool rflag = false;
+	bool sflag = false;
+	bool vflag = false;
+	char c;
+	struct utsname u;
+
+	while((c = getopt(argc, argv, "amnrsv")) != -1)
+		switch(c) {
+		case 'a':
+			mflag = nflag = rflag = sflag = vflag = true;
+			break;
+		case 'm':
+			mflag = true;
+			break;
+		case 'n':
+			nflag = true;
+			break;
+		case 'r':
+			rflag = true;
+			break;
+		case 's':
+			sflag = true;
+			break;
+		case 'v':
+			vflag = true;
+			break;
+		default:
+			exit(EXIT_FAILURE);
+		}
+	if(uname(&u) == -1)
+		eprintf("uname failed:");
+
+	if(sflag || !(nflag || rflag || vflag || mflag))
+		printf("%s ", u.sysname);
+	if(nflag)
+		printf("%s ", u.nodename);
+	if(rflag)
+		printf("%s ", u.release);
+	if(vflag)
+		printf("%s ", u.version);
+	if(mflag)
+		printf("%s ", u.machine);
+	putchar('\n');
+	return EXIT_SUCCESS;
+}