symbols.  Use it for all definitions of non-static variables and functions.

lexyy.c, make_flex.sh: Declare yylex as UNIV_INTERN, not static.  It is
referenced from pars0grm.c.

Actually, according to
	nm .libs/ha_innodb.so|grep -w '[ABCE-TVXYZ]'
the following symbols are still global:

* The vtable for class ha_innodb
* pars0grm.c: The function yyparse() and the variables yychar, yylval, yynerrs

The required changes to the Bison-generated file pars0grm.c will be addressed
in a separate commit, which will add a script similar to make_flex.sh.

The class ha_innodb is renamed from class ha_innobase by a #define.  Thus,
there will be no clash with the builtin InnoDB.  However, there will be some
overhead for invoking virtual methods of class ha_innodb.  Ideas for making
the vtable hidden are welcome.  -fvisibility=hidden is not available in GCC 3.