Use http_build_query compat function

[simonwheatley]

We now have the compat function http_build_query so should use it rather than _http_build_query wherever possible. The first attached diff (use http_build_query in WP_Http.diff) simplifies WP_Http by removing a conditional, and the second (use http_build_query in WP_Http.diff) switched build_query to use http_build_query rather than _http_build_query.

Relevant: #9044

[dd32]

The 3rd separator argument was added in PHP 5.2.1, in previous versions it may use '&' as the separator. Due to the way those functions are being used, We need to specify it as & to retain complete compatibility.

We could simply use _http_build_query() in class-http.php, but if the core function is available.. might as well use it..

[wonderboymusic]

the WP_Http part was fixed in [17535] - I refreshed the build_query() part against trunk in 13452.diff​

[dd32]

_http_build_query() and http_build_query() are not direct replacements of each other, Plus, the 4th arg to http_build_query() was added in PHP 5.4.0.

Above patch won't work, I'm pretty sure this is wontfix as the functions are going to be incompatible.

[wonderboymusic]

as per dd32