Cleanup a few of the more egregiously broken sysconf values to

actually match reality.  In particular, _SC_GETPW_R_SIZE_MAX and
_SC_GETGR_R_SIZE_MAX were causing us problems with programs such
as libglib, since they were always returning -1, which is a bit
smaller than the actual passwd and group max buffer sizes.
 -Erik

libc/pwd_grp/pwd_grp.c

@@ -49,6 +49,8 @@
 /**********************************************************************/
 /* Sizes for staticly allocated buffers. */
 
+/* If you change these values, also change _SC_GETPW_R_SIZE_MAX and
+ * _SC_GETGR_R_SIZE_MAX in libc/unistd/sysconf.c to match */
 #define PWD_BUFFER_SIZE 256
 #define GRP_BUFFER_SIZE 256
 

libc/termios/ttyname.c

@@ -21,6 +21,8 @@
  * However, there is no need to waste space and support non-standard
  * tty names either.  So we compromise and use the following buffer
  * length.  (Erik and Manuel agreed that 32 was more than reasonable.)
+ *
+ * If you change this, also change _SC_TTY_NAME_MAX in libc/unistd/sysconf.c
  */
 #define TTYNAME_BUFLEN		32
 

libc/unistd/sysconf.c

@@ -103,11 +103,7 @@ long int __sysconf(int name)
 #endif
 
     case _SC_OPEN_MAX:
-#if 1
       RETURN_FUNCTION(getdtablesize());
-#else
-      RETURN_NEG_1;
-#endif
 
     case _SC_STREAM_MAX:
 #ifdef	STREAM_MAX
@@ -117,12 +113,7 @@ long int __sysconf(int name)
 #endif
 
     case _SC_TZNAME_MAX:
-#if 0
-      RETURN_FUNCTION(tzname_max ());
-#else
-/*       RETURN_NEG_1; */
       return _POSIX_TZNAME_MAX;
-#endif
 
     case _SC_JOB_CONTROL:
 #ifdef	_POSIX_JOB_CONTROL
@@ -559,46 +550,39 @@ long int __sysconf(int name)
 
       /* POSIX 1003.1c (POSIX Threads).  */
     case _SC_THREADS:
-#ifdef	_POSIX_THREADS
+#ifdef __UCLIBC_HAS_THREADS__
       return 1;
 #else
       RETURN_NEG_1;
 #endif
 
     case _SC_THREAD_SAFE_FUNCTIONS:
-#ifdef	_POSIX_THREAD_SAFE_FUNCTIONS
+#ifdef __UCLIBC_HAS_THREADS__
       return 1;
 #else
       RETURN_NEG_1;
 #endif
 
+/* If you change these, also change libc/pwd_grp/pwd_grp.c to match */
+#define PWD_BUFFER_SIZE 256
+#define GRP_BUFFER_SIZE 256
     case _SC_GETGR_R_SIZE_MAX:
-#ifdef	NSS_BUFLEN_GROUP
-      return NSS_BUFLEN_GROUP;
-#else
-      RETURN_NEG_1;
-#endif
+      return GRP_BUFFER_SIZE;
 
     case _SC_GETPW_R_SIZE_MAX:
-#ifdef	NSS_BUFLEN_PASSWD
-      return NSS_BUFLEN_PASSWD;
-#else
-      RETURN_NEG_1;
-#endif
+      return PWD_BUFFER_SIZE;
 
+/* getlogin() is a worthless interface.  In uClibc we let the user specify
+ * whatever they want via the LOGNAME environment variable, or we return NULL
+ * if getenv() fails to find anything.  So this is merely how large a env
+ * variable can be.  Lets use 256 */
     case _SC_LOGIN_NAME_MAX:
-#ifdef	_POSIX_LOGIN_NAME_MAX
-      return _POSIX_LOGIN_NAME_MAX;
-#else
-      RETURN_NEG_1;
-#endif
+      return 256;
 
+/* If you change this, also change _SC_TTY_NAME_MAX in libc/unistd/sysconf.c */
+#define TTYNAME_BUFLEN		32
     case _SC_TTY_NAME_MAX:
-#ifdef	_POSIX_TTY_NAME_MAX
-      return _POSIX_TTY_NAME_MAX;
-#else
-      RETURN_NEG_1;
-#endif
+      return TTYNAME_BUFLEN;
 
     case _SC_THREAD_DESTRUCTOR_ITERATIONS:
 #ifdef	_POSIX_THREAD_DESTRUCTOR_ITERATIONS