Update www/php-apc to latest 3.1.2

Changes in 3.1.2:
- pecl package.xml/build fixes (bjori)

Changes in 3.1.1:
- PHP4 compatibilty break
- apc_pool allocator (Gopal)
- doubly-linked sma allocator (Shire)
- php 5.3 gc compatibility (Gopal)
- APCIterator for easy access (Shire)
- apc_delete_file (Shire)
- apc_inc/apc_dec/apc_cas functions (Shire)
- apc.canonicalize (Gopal)
- apc.preload_path (Gopal)
- apc.rfc1867_ttl (Shire)
- apc.file_md5 (Shire)
- consolidate locking macros (Shire)
- remove futex/TSRM locks (Shire)
- non-blocking semaphore locks (Shire)
- zval* object rework (Gopal)

Mark this package PHP5-only

(jdolecek)