TT_Vary_Apply_Glyph_Deltas zeroes lsb deltas when HVAR is present but missing lsb mapping
I've just updated to the most recent version of FreeType and discovered some discrepancies (horizontal shifts) in TrueType VF outlines.
Looks like the change was introduced in this commit: 705f4161
In the original code, phantom point deltas were zeroed based on individual flags for lsb, hadvance, tsb and vadvance. The new code only checks the advance flags and zeroes the respective side-bearing deltas based on those. The effect is that fonts with [H|V]VAR but missing side-bearing mappings will not apply the appropriate side-bearing deltas. In the case of the first phantom point, this can lead to incorrect horizontal placement of outlines.