[OTS] Add support for the MATH table.

src/layout.h

Index: src/layout.h
diff --git a/src/layout.h b/src/layout.h
index 7a1589cec76d9111d12bc6fc1f7bd07fcf610985..d0af43d5c73ef5bb18c7ce231d1139acb540cc74 100644
--- a/src/layout.h
+++ b/src/layout.h
@@ -44,7 +44,8 @@ bool ParseClassDefTable(const uint8_t *data, size_t length,
                         const uint16_t num_classes);
 
 bool ParseCoverageTable(const uint8_t *data, size_t length,
-                        const uint16_t num_glyphs);
+                        const uint16_t num_glyphs,
+                        const uint16_t expected_num_glyphs = 0);
 
 bool ParseDeviceTable(const uint8_t *data, size_t length);