Fix compilation on windows with editorconfig-c-core available

Summary:
On Windows the library was found during config, but not during compilation without the variable EditorConfig_LIBRARIES.

Reviewers: cullmann, Kate

Reviewed By: cullmann, Kate

Subscribers: dhaumann, kwrite-devel, Frameworks

Tags: Frameworks

Differential Revision: https://phabricator.kde.org/D7443