[test] Build with HB_MINI

Also add CONFIG.md instructions for building configs with meson.

Fixes https://github.com/harfbuzz/harfbuzz/issues/4760

CONFIG.md

@@ -130,6 +130,10 @@ The pre-defined configurations are:
     disabling thread-safety and debugging, and use even more size-optimized data
     tables.
 
+To setup the build with these options use something like:
+```
+$ meson setup build -Dcpp_args=-DHB_MINI -Dc_args=-DHB_MINI
+```
 
 ## Tailoring configuration
 
@@ -155,4 +159,4 @@ Note that the config option `HB_NO_CFF`, which is enabled by `HB_LEAN` and
 `HB_TINY` does *not* mean that the resulting library won't work with CFF fonts.
 The library can shape valid CFF fonts just fine, with or without this option.
 This option disables (among other things) the code to calculate glyph extents
-for CFF fonts, which many clients might not need.
+for CFF fonts or draw them, which many clients might not need.

src/hb-subset-plan.cc

@@ -491,7 +491,7 @@ _collect_base_variation_indices (hb_subset_plan_t* plan)
   base->collect_variation_indices (plan, varidx_set);
   const OT::ItemVariationStore &var_store = base->get_var_store ();
   unsigned subtable_count = var_store.get_sub_table_count ();
-  
+
 
   _remap_variation_indices (var_store, varidx_set,
                             plan->normalized_coords,
@@ -731,7 +731,7 @@ _populate_unicodes_to_retain (const hb_set_t *unicodes,
       plan->codepoint_to_glyph->alloc (unicodes->get_population () + glyphs->get_population ());
 
       auto &gid_to_unicodes = plan->accelerator->gid_to_unicodes;
-      
+
       for (hb_codepoint_t gid : *glyphs)
       {
         auto unicodes = gid_to_unicodes.get (gid);

test/api/test-aat-layout.c

@@ -33,6 +33,8 @@
 static hb_face_t *face;
 static hb_face_t *sbix;
 
+#ifndef HB_NO_AAT
+
 static void
 test_aat_get_feature_types (void)
 {
@@ -114,15 +116,19 @@ test_aat_has (void)
   hb_face_destroy (trak);
 }
 
+#endif
+
 int
 main (int argc, char **argv)
 {
   unsigned int status;
   hb_test_init (&argc, &argv);
 
+#ifndef HB_NO_AAT
   hb_test_add (test_aat_get_feature_types);
   hb_test_add (test_aat_get_feature_selectors);
   hb_test_add (test_aat_has);
+#endif
 
   face = hb_test_open_font_file ("fonts/aat-feat.ttf");
   sbix = hb_test_open_font_file ("fonts/chromacheck-sbix.ttf");

test/api/test-ot-face.c

@@ -76,6 +76,7 @@ test_font (hb_font_t *font, hb_codepoint_t cp)
   hb_ot_color_has_png (face);
   hb_blob_destroy (hb_ot_color_glyph_reference_png (font, cp));
 
+#ifndef HB_NO_AAT
   {
     hb_aat_layout_feature_type_t feature = HB_AAT_LAYOUT_FEATURE_TYPE_ALL_TYPOGRAPHIC;
     unsigned count = 1;
@@ -87,6 +88,7 @@ test_font (hb_font_t *font, hb_codepoint_t cp)
     hb_aat_layout_feature_type_get_selector_infos (face, HB_AAT_LAYOUT_FEATURE_TYPE_DESIGN_COMPLEXITY_TYPE, 0, &count, &setting, &default_index);
     result += count + feature + setting.disable + setting.disable + setting.name_id + setting.reserved + default_index;
   }
+#endif
 
   hb_set_t *lookup_indexes = hb_set_create ();
   hb_set_add (lookup_indexes, 0);

test/fuzzing/hb-fuzzer.hh

@@ -1,3 +1,5 @@
+#include <hb-config.hh>
+
 #include <hb.h>
 #include <stddef.h>