Blender Git Loki

Cleanup: Move private/internal operator state data out of public header for GPencil module

This commit moves the defines for several modal operators
(Interpolate, Fill, and Add Primitives) out of the editors/gpencil
module's public headerfile ("ED_gpencil.h") into the module's
internal headerfile ("gpencil_intern.h").

We should not be spraying the internal implementation details of
operators in public headers. In this case, these defines weren't
even being used outside of the gpencil module - they were only
put in a header so that drawgpencil.c (which lives in the same
module) could access this data (and even then, I wonder those
callbacks need access to everything).

Note: I couldn't get rid of the ED_numinput.h include in the header
yet, as several of the operators define NumInput members inline.