Linking in anything anywhere does not make it GPL. The question is if it’s OK to distribute the code if it’s not GPL… I take it as You mean it is.
How to interpret this then:
Not OK is:
Author publishes a Blender script, calling a compiled C library with own code, both under own license.
And it can’t really make a difference if the C library is own code or not… This is supposed to make it clearer:
The divider is “If the script runs in the Blender Interpretor”. When the script calls code not running in the Blender Interpretor you are making bindings to other facilities, and the regular GNU GPL rules apply.
Gnash… but the first ok is probably most confusing:
Author publishes a Blender script mixed with own code, under own license.