The SCM_xxx_CHARS macros return pointers to internal scheme data and

[David Hampton]

Log Message:
-----------
The SCM_xxx_CHARS macros return pointers to internal scheme data and
should be treated as const.  Use the compiler to enforce this
restriction.

Tags:
----
gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/app-utils:
        option-util.c
    gnucash/src/engine:
        engine-helpers.c
        glib-helpers.c
        kvp-scm.c
    gnucash/src/gnome-utils:
        argv-list-converters.c
        dialog-options.c
        gnc-menu-extensions.c