package/php_zmq: fix build with php 7.3.0

package/php_zmq: fix build with php 7.3.0

This includes an patch that fixes the following error:

```
/home/buildroot/build/instance-0/output/build/php-zmq-1.1.3/zmq.c: In function 'php_zmq_context_get':
/home/buildroot/build/instance-0/output/build/php-zmq-1.1.3/zmq.c:238:20: error: lvalue required as left operand of assignment
   GC_REFCOUNT(&le) = 1;
                    ^
/home/buildroot/build/instance-0/output/build/php-zmq-1.1.3/zmq.c: In function 'php_zmq_socket_store':
/home/buildroot/build/instance-0/output/build/php-zmq-1.1.3/zmq.c:538:19: error: lvalue required as left operand of assignment
  GC_REFCOUNT(&le) = 1;
```

The patch was created from the PR at:

https://github.com/mkoppanen/php-zmq/pull/195

Upstream has not merged the PR. Fixes:

http://autobuild.buildroot.org/results/3f2/3f258fbc7352c3d7205bc6402145be1102d69683

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>