IS_INTERNED for apc + zend mixtures

Hi,

I'm trying to fix apc for php 5.4 and the primary issue seems to be
the actual check inside IS_INTERNED.

#define IS_INTERNED(s) \
	(((s) >= CG(interned_strings_start)) && ((s) < CG(interned_strings_end)))

Except when apc does implement interned strings, there are two
blocks which qualify to be interned. The one that zend maintains
in the original CG which allocates things like the "stdClass"
string.

So I end up with a double free error on this

==32196== Invalid free() / delete / delete[]
==32196==    at 0x4C270BD: free (vg_replace_malloc.c:366)
==32196==    by 0x68FA14: destroy_zend_class (zend_opcode.c:331)
==32196==    by 0x6A52B2: zend_hash_clean (zend_hash.c:596)
==32196==    by 0x705F6FF: apc_interned_strings_shutdown (apc_string.c:226)
==32196==    by 0x70579A9: apc_module_shutdown (apc_main.c:895)
==32196==    by 0x704E02E: zm_shutdown_apc (php_apc.c:373)
==32196==    by 0x69E0A4: module_destructor (zend_API.c:2248)
==32196==    by 0x6A4CC6: zend_hash_apply_deleter (zend_hash.c:650)
==32196==    by 0x6A4F67: zend_hash_graceful_reverse_destroy 
(zend_hash.c:687)
==32196==    by 0x6989F2: zend_shutdown (zend.c:806)
==32196==    by 0x63C48C: php_module_shutdown (main.c:2264)
==32196==    by 0x742824: main (php_cli.c:1371)
==32196==  Address 0x6c58a68 is 84,600 bytes inside a block of size 
1,048,576 alloc'd
==32196==    at 0x4C274A8: malloc (vg_replace_malloc.c:236)
==32196==    by 0x6B888C: zend_interned_strings_init (zend_string.c:48)
==32196==    by 0x699A65: zend_startup (zend.c:740)
==32196==    by 0x63D9F4: php_module_startup (main.c:1936)
==32196==    by 0x740C7C: php_cli_startup (php_cli.c:414)
==32196==    by 0x7425C8: main (php_cli.c:1336)

We probably need an override for that so that we can nest multiple
interned blocks which are non contiguous between different modules.

Cheers,
Gopal