Known Bugs
 
1.   Gallery2 doesn't work with PHP5+APC.  There is something wrong
     with the way methods are restored in some edge case I haven't
     been able to figure out yet.
     To reproduce install gallery2 and click down to an individual photo.

2.   apc_store() probably needs some checks to skip trying to store
     internal classes.  Something along the lines of:

     if(Z_TYPE_P(val) == IS_OBJECT) {
        zend_class_entry *ce = Z_OBJCE_P(val);
        if(ce->type == ZEND_INTERNAL_CLASS) {
            php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot cache internal objects");
            RETURN_FALSE;
        }
     }

     in the apc_store() function in php_apc.c but I am wondering if it needs to do more
     than that.

Windows

1.   The following configurations (build arguments) have not been implemented yet

          (*) --enable-apc-mmap         	Memory mapping support
          (*) --enable-apc-sem         		Semaphore locking support (FCNTL replacement)
          (*) --enable-apc-phreadmutex		Thread mutexes, while implemented we should probably rename the internals to thread
	  (*) --enable-apc-pthreadrwlocks	Thread mutexes, read/write locking

2.   Non-blocking locks is not supported either

3.   Update fileinfo to support stat info in a more portable way (see PECL #17903)

4.   Check whether the signal handling needs to be enabled, and if it makes sense on Windows