Fixes for ZPP string arguments (and stuff)

[datibbaw]

I stepped through all usages of zend_parse_parameters() in all core extensions except for ext/standard to make sure the correct type is used for the string length.

At the same time I've looked at overzealous replacements of int with size_t; some values work with negative numbers and as such should remain as int.

Finally, some minor inconsistencies were addressed.

This is a PR for two reasons:

1. Gather more feedback before submission
2. Let it run through Travis CI

[nikic]

deadlock_count doesn't sound very size_tish. Also used with %d below.

[datibbaw]

Fixed! 😺

[jpauli]

Is this PR still relevant now ?
I think most of work has been implemented so far

[nikic]

There are still relevant parts here. One change in interbase.c and several in mbstring relating to the mbfl_string structure.

I wonder how mbfl_string interacts with our ABI, can we change it in a patch release?

[nikic]

Interbase fix: a7028d9

We do export the mbfl_string structure in headers, so can't change it for 7.0. So we should port mbfl to use size_t in master and use the solution in this PR for 7.0.

[weltling]

@nikic you are right! mbfl_string is not compatible with zend_string on 64-bit, thanks for being aware. I've pushed this 89a4342 to fix the most of issue. There is probably some more to go, but almost nothing to do with incompatible pointers for string lengths.

Thanks.

[nikic]

@weltling Thanks! With that commit all changes from this PR should be covered, so closing here.