gcc7 warning:

sql/table.cc: In member function ‘int TABLE_SHARE::init_from_binary_frm_image(THD*, bool, const uchar*, size_t)’:
sql/table.cc:2032:11: warning: this statement may fall through [-Wimplicit-fallthrough=]
           if (vers_can_native)
           ^~
sql/table.cc:2037:9: note: here
         default:
         ^~~~~~~