(vhdl-mode-map-init): Don't override default
TAB binding so tab-always-indent is obeyed.
(vhdl-minibuffer-local-map): Move initialization into declaration.
(vhdl-mode-abbrev-table-init): Mark the abbrevs as `system'.
(vhdl-run-when-idle, vhdl-create-mode-menu, vhdl-character-to-event)
(vhdl-hooked-abbrev): Avoid test for XEmacs.
(vhdl-current-line): Use line-beginning-position.
(vhdl-doc-variable, vhdl-doc-mode): Call help-setup-xref before
with-output-to-temp-buffer, so the current position can be recorded.