* posix/getconf.c (vars): Add _SC_ values for cache information.
* sysdeps/generic/bits/confname.h: Add _SC_* values for cache
information.
* sysdeps/unix/sysv/linux/sysconf.c (__sysconf): Reorganize to
allow yet another sysconf function to include the one in this file.
* sysdeps/unix/sysv/linux/i386/sysconf.c: New file.
* sysdeps/generic/sysconf.c: Add default handling for cache line info.