EZC: fix ProxyArray compilation with ENABLE_ZEND_COMPAT=OFF

When ENABLE_ZEND_COMPAT is off:
* In zend-wrap-func.h, define zBoxAndProxy() as well as zend_wrap_func,
  since both are now referenced from outside ext_zend_compat
* Set ZVAL_PTR_DTOR to be a local empty function, to avoid a linker
  error.
Don't require full source tree for building DSOs

* Install header files
* Install CMake files needed by hphpize
* Fix hphpize to look for headers and CMake files in the installed
  directory
* Rename php_config.h-linux to php_config-linux.h and
  php_config.h-darwin to php_config-darwin.h, so that it will be
  picked up by *.h glob for installation. Also helps with syntax
  highlighting.

Also:
* Add an install target to the makefile of DSOs. Install to a
  version-dependent directory, similar to what PHP does. I chose
  lib/hphp over lib/hhvm for consistency with include/hphp.