Fix sysconf(3) for _SC_GETGR_R_SIZE_MAX and _SC_GETPW_R_SIZE_MAX.

Change-Id: Ie16cb21c1a5a2bdce8502b5974e2c4dbb1d679ce
diff --git a/libc/bionic/sysconf.cpp b/libc/bionic/sysconf.cpp
index 5e39e61..9ab2007 100644
--- a/libc/bionic/sysconf.cpp
+++ b/libc/bionic/sysconf.cpp
@@ -298,8 +298,8 @@
     case _SC_TIMERS:            return _POSIX_TIMERS;
 #endif
 
-    // GETGR_R_SIZE_MAX ?
-    // GETPW_R_SIZE_MAX ?
+    case _SC_GETGR_R_SIZE_MAX: return 1024;
+    case _SC_GETPW_R_SIZE_MAX: return 1024;
 
     case _SC_LOGIN_NAME_MAX:    return SYSTEM_LOGIN_NAME_MAX;