Update Android port

* src/sfnt.c (xmalloc, xrealloc): Improve behavior upon
allocation failures during test.
(sfnt_table_names): Add prep.
(sfnt_transform_coordinates): Allow applying offsets during
coordinate transform.
(sfnt_decompose_compound_glyph): Defer offset computation until
any component compound glyph is loaded, then apply it during the
transform process.

(sfnt_multiply_divide): Make available everywhere.  Implement on
64 bit systems.
(sfnt_multiply_divide_signed): New function.
(sfnt_mul_fixed): Fix division overflow.

(sfnt_curve_to_and_build_1, sfnt_build_glyph_outline): Remove
outdated comment.
(sfnt_build_outline_edges): Fix coding style.
(sfnt_lookup_glyph_metrics): Allow looking up metrics without
scaling.
(struct sfnt_cvt_table): Fix type of cvt values.
(struct sfnt_prep_table): New structure.
(sfnt_read_cvt_table): Read cvt values in terms of fwords, not
longs (as Apple's doc seems to say).
(sfnt_read_fpgm_table): Fix memory allocation for font program
table.
(sfnt_read_prep_table): New function.
(struct sfnt_interpreter_zone): New structure.
(struct sfnt_interpreter_graphics_state): New fields `project',
`move', `vector_dot_product'.  Rename to `sfnt_graphics_state'.
(struct sfnt_interpreter, sfnt_mul_f26dot6): Stop doing rounding
division.
(sfnt_init_graphics_state):
(sfnt_make_interpreter):
(MOVE):
(SSW):
(RAW):
(SDS):
(ADD):
(SUB):
(ABS):
(NEG):
(WCVTF):
(_MIN):
(S45ROUND):
(SVTCAx):
(sfnt_set_srounding_state):
(sfnt_skip_code):
(sfnt_interpret_unimplemented):
(sfnt_interpret_fdef):
(sfnt_interpret_idef):
(sfnt_interpret_if):
(sfnt_interpret_else):
(sfnt_round_none):
(sfnt_round_to_grid):
(sfnt_round_to_double_grid):
(sfnt_round_down_to_grid):
(sfnt_round_up_to_grid):
(sfnt_round_to_half_grid):
(sfnt_round_super):
(sfnt_validate_gs):
(sfnt_interpret_run):
(sfnt_interpret_font_program):
(struct sfnt_test_dcontext):
(sfnt_test_move_to):
(sfnt_test_line_to):
(sfnt_test_curve_to):
(sfnt_test_get_glyph):
(sfnt_test_free_glyph):
(sfnt_test_span):
(sfnt_test_edge_ignore):
(sfnt_test_edge):
(sfnt_test_raster):
(test_interpreter_profile):
(test_cvt_values):
(test_interpreter_cvt):
(test_interpreter_head):
(sfnt_make_test_interpreter):
(struct sfnt_interpreter_test):
(sfnt_run_interpreter_test):
(struct sfnt_generic_test_args):
(sfnt_generic_check):
(sfnt_check_srp0):
(sfnt_check_szp0):
(sfnt_check_sloop):
(struct sfnt_rounding_test_args):
(sfnt_check_rounding):
(sfnt_check_smd):
(sfnt_check_scvtci):
(sfnt_check_sswci):
(sfnt_check_ssw):
(sfnt_check_flipon):
(sfnt_check_flipoff):
(npushb_test_args):
(npushw_test_args):
(pushb_test_args):
(pushw_test_args):
(stack_overflow_test_args):
(stack_underflow_test_args):
(rtg_test_args):
(rtg_symmetric_test_args):
(rtg_1_test_args):
(rtg_1_symmetric_test_args):
(rthg_test_args):
(rthg_1_test_args):
(rtdg_test_args):
(rtdg_1_test_args):
(rtdg_2_test_args):
(rtdg_3_test_args):
(else_test_args):
(jmpr_test_args):
(dup_test_args):
(pop_test_args):
(clear_test_args):
(swap_test_args):
(depth_test_args):
(cindex_test_args):
(mindex_test_args):
(raw_test_args):
(loopcall_test_args):
(call_test_args):
(fdef_test_args):
(fdef_1_test_args):
(endf_test_args):
(ws_test_args):
(rs_test_args):
(wcvtp_test_args):
(rcvt_test_args):
(mppem_test_args):
(mps_test_args):
(debug_test_args):
(lt_test_args):
(all_tests):
(main): Implement more instructions.

* src/sfnt.h (enum sfnt_table, struct sfnt_glyph_metrics): Add
new tables.  Add comment.

src/sfnt.h

@@ -45,6 +45,7 @@ enum sfnt_table
     SFNT_TABLE_META,
     SFNT_TABLE_CVT ,
     SFNT_TABLE_FPGM,
+    SFNT_TABLE_PREP,
   };
 
 #define SFNT_ENDOF(type, field, type1)			\
@@ -758,10 +759,16 @@ struct sfnt_hmtx_table
 struct sfnt_glyph_metrics
 {
   /* Distance between origin and left edge of raster.  Positive
-     changes move rightwards.  */
+     changes move rightwards.
+
+     If sfnt_lookup_glyph_metrics is given a pixel size of -1,
+     this is actually a sign extended fword.  */
   sfnt_fixed lbearing;
 
-  /* Advance to next glyph's origin.  */
+  /* Advance to next glyph's origin.
+
+     If sfnt_lookup_glyph_metrics is given a pixel size of -1, this is
+     actually a sign extended fword.  */
   sfnt_fixed advance;
 };