(mark_backtrace): Define only if BYTE_MARK_STACK.
* xdisp.c (message_enable_multibyte): Now static.
- Declare Lisp_Object Q* variables to be 'static' if not exproted.
+ Declare Lisp_Object Q* variables to be 'static' if not exported.
This makes it easier for human readers (and static analyzers)
to see whether these variables are used from other modules.
* alloc.c, buffer.c, bytecode.c, callint.c, casetab.c, category.c: