provide a utsname structure

ZFS wants direct access to a global utsname structure.  Provide one from
core OSv code and rewrite uname to just copy it out.  To ease this move
the uname implementation to a C file as this allows using designated
initializers and avoids the casting mess around memcpy.

libc/build.mak

@@ -340,6 +340,7 @@ libc += misc/getopt_long.o
 libc += misc/getsubopt.o
 libc += misc/realpath.o
 libc += misc/backtrace.o
+libc += misc/uname.o
 
 libc += multibyte/btowc.o
 libc += multibyte/internal.o

libc/libc.cc

@@ -97,17 +97,6 @@ struct passwd* getpwuid(uid_t uid)
     }
 }
 
-int uname(struct utsname* u)
-{
-    // lie, to avoid confusing the payload.
-    strcpy(u->sysname, "Linux");
-    strcpy(u->nodename, "osv.local");
-    strcpy(u->release, "3.7");
-    strcpy(u->version, "#1 SMP");
-    strcpy(u->machine, "x86_64");
-    return 0;
-}
-
 int sched_yield()
 {
     sched::thread::yield();

libc/misc/uname.c

 #include <sys/utsname.h>
 #include <string.h>
-#include "syscall.h"
+
+struct utsname utsname = {
+	.sysname	= "Linux",	/* lie, to avoid confusing the payload. */
+	.nodename	= "osv.local",
+	.release	= "3.7",
+	.version	= "#1 SMP",
+	.machine	= "x86_64",
+};
 
 int uname(struct utsname *uts)
 {
-	return syscall(SYS_uname, uts);
+	memcpy(uts, &utsname, sizeof(struct utsname));
+	return 0;
 }