stb_truetype: tweaks to codepoint-missing packing

stb_truetype.h

@@ -643,11 +643,11 @@ STBTT_DEF void stbtt_PackSetOversampling(stbtt_pack_context *spc, unsigned int h
 // To use with PackFontRangesGather etc., you must set it before calls
 // call to PackFontRangesGatherRects.
 
+STBTT_DEF void stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip);
 // If skip != 0, this tells stb_truetype to skip any codepoints for which
 // there is no corresponding glyph. If skip=0, which is the default, then
 // codepoints without a glyph recived the font's "missing character" glyph,
 // typically an empty box by convention.
-STBTT_DEF void stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip);
 
 STBTT_DEF void stbtt_GetPackedQuad(const stbtt_packedchar *chardata, int pw, int ph,  // same data as above
                                int char_index,             // character to display
@@ -677,7 +677,7 @@ struct stbtt_pack_context {
    int   height;
    int   stride_in_bytes;
    int   padding;
-   int   skip_empty;
+   int   skip_missing;
    unsigned int   h_oversample, v_oversample;
    unsigned char *pixels;
    void  *nodes;
@@ -3806,6 +3806,7 @@ STBTT_DEF int stbtt_PackBegin(stbtt_pack_context *spc, unsigned char *pixels, in
    spc->stride_in_bytes = stride_in_bytes != 0 ? stride_in_bytes : pw;
    spc->h_oversample = 1;
    spc->v_oversample = 1;
+   spc->skip_missing = 0;
 
    stbrp_init_target(context, pw-padding, ph-padding, nodes, num_nodes);
 
@@ -3833,7 +3834,7 @@ STBTT_DEF void stbtt_PackSetOversampling(stbtt_pack_context *spc, unsigned int h
 
 STBTT_DEF void stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip)
 {
-   spc->skip_empty = skip;
+   spc->skip_missing = skip;
 }
 
 #define STBTT__OVER_MASK  (STBTT_MAX_OVERSAMPLE-1)
@@ -3989,7 +3990,7 @@ STBTT_DEF int stbtt_PackFontRangesGatherRects(stbtt_pack_context *spc, const stb
          int x0,y0,x1,y1;
          int codepoint = ranges[i].array_of_unicode_codepoints == NULL ? ranges[i].first_unicode_codepoint_in_range + j : ranges[i].array_of_unicode_codepoints[j];
          int glyph = stbtt_FindGlyphIndex(info, codepoint);
-         if (glyph == 0 && spc->skip_empty) {
+         if (glyph == 0 && spc->skip_missing) {
             rects[k].w = rects[k].h = 0;
          } else {
             stbtt_GetGlyphBitmapBoxSubpixel(info,glyph,