SImplify the functionality of script_concat_settings() and remove the globals

[azaozz]

As discussed in the comments on #20055, script_concat_settings() should be split into couple of simple functions that only check the constants and the 'can_compress_scripts' server option.

[azaozz]

There's an initial patch by ericlewis: ​http://core.trac.wordpress.org/attachment/ticket/20055/20055-3.patch

Not sure what the best back-compat option is here. Outright removing the globals would break plugins that use them. Seems we should move script_concat_settings() to deprecated.php and trigger the appropriate "deprecated" messages.

Then we can introduce simplified function that would return whether compression from PHP is supported by the server using CONCATENATE_SCRIPTS, COMPRESS_SCRIPTS and get_site_option('can_compress_scripts').

[azaozz]

This didn't make it in 3.4.

[jeremyfelt]

Hunting around what compression_test() actually does and impacts drove me crazy today. Is there still interest in cleaning this up?

[chriscct7]

Closing as maybelater. Complete lack of interest on the feature on the ticket over the last 3 years. Feel free to reopen when more interest re-emerges (particularly if there's a patch).