[truetype] Prevent bytecode reuse after the interpretation error.

* src/truetype/ttinterp.c (free_buffer_in_size): New function to
free the buffer allocated during the interpretation of this glyph.
(TT_RunIns): Unset FT_Face->size->{cvt_ready,bytecode_ready} if
an error occurs in the bytecode interpretation.  The interpretation
of invalid bytecode may break the function definitions and referring
them in later interpretation is danger.  By unsetting these flags,
`fpgm' and `prep' tables are executed again in next interpretation.

Fix Savannah bug #30798, reported by Robert Swiecki.
2 files changed