This fixes the only other instance I could find of the use of an opaque
enum declaration.  The enum type is defined inside defs.h, so I simply
included this file, and removed the enum declaration.

2007-12-19  Joel Brobecker  <brobecker@adacore.com>

        * symtab.h: #include "defs.h".
        (enum language): Remove opaque declaration.
        * Makefile.in (symtab_h): Update dependencies.

Tested on x86-linux by rebuilding GDB.
Checked in.

-- 
Joel