added _SC_LOGIN_NAME_MAX method for sysconf() - which just returns L_cuserid from stdio.h

Reference: /n/sources/patch/applied/sysconf-extra
Date: Tue Dec 16 13:23:56 CET 2008
Signed-off-by: steve@quintile.net

--- /sys/src/ape/lib/ap/posix/sysconf.c	Tue Dec 16 13:22:54 2008
+++ /sys/src/ape/lib/ap/posix/sysconf.c	Tue Dec 16 13:22:52 2008
@@ -1,3 +1,4 @@
+#include	<stdio.h>
 #include	<unistd.h>
 #include	<limits.h>
 #include	<time.h>
@@ -33,6 +34,8 @@
 #endif
 	case _SC_VERSION:
 		return _POSIX_VERSION;
+	case _SC_LOGIN_NAME_MAX:
+		return L_cuserid;
 	}
 	errno = EINVAL;
 	return -1;
--- /sys/include/ape/unistd.h	Tue Dec 16 13:22:58 2008
+++ /sys/include/ape/unistd.h	Tue Dec 16 13:22:56 2008
@@ -61,6 +61,7 @@
 #define	_SC_JOB_CONTROL		8	/* posix job control */
 #define	_SC_SAVED_IDS		9	/* saved suid/sgid per process */
 #define	_SC_VERSION		10	/* this version */
+#define _SC_LOGIN_NAME_MAX	11	/* max length of a login name */
 
 /* pathconf argument */
 #define _PC_LINK_MAX		1