[style] New experimental API, hb_style_get_value

Searches variation axes of a hb_font_t object for a specific axis first,
if not set, then tries to get default style values from different
tables of the font.

src/hb-ot-face-table-list.hh

diff --git a/src/hb-ot-face-table-list.hh b/src/hb-ot-face-table-list.hh
index 6fa9baf..5519d4f 100644
--- a/src/hb-ot-face-table-list.hh
+++ b/src/hb-ot-face-table-list.hh
@@ -53,13 +53,14 @@
 HB_OT_TABLE (OT, hhea)
 HB_OT_ACCELERATOR (OT, hmtx)
 HB_OT_TABLE (OT, OS2)
-#if !defined(HB_NO_OT_FONT_GLYPH_NAMES) || !defined(HB_NO_METRICS)
+#if !defined(HB_NO_OT_FONT_GLYPH_NAMES) || !defined(HB_NO_METRICS) || !defined(HB_NO_STYLE)
 HB_OT_ACCELERATOR (OT, post)
 #endif
 #ifndef HB_NO_NAME
 HB_OT_ACCELERATOR (OT, name)
 #endif
-#ifndef HB_NO_STAT
+#ifndef HB_NO_STYLE
+HB_OT_TABLE (AAT, fdsc)
 HB_OT_TABLE (OT, STAT)
 #endif
 #ifndef HB_NO_META