Avoid warnings from clang in the runtime and util directories.

runtime/mercury_stack_trace.c:
	In the function MR_dump_stack_from_layout_clique initialise the variable
	lines_dumped_so_far.  (This appears to be an actual bug.)

runtime/mercury_prof.c:
	Only define the static global in_profiling_code if either of call count
	profiling or time profiling is enabled.

runtime/mercury_context.c:
runtime/mercury_deconstruct.c:
runtime/mercury_deep_profiling.c:
	Only define some local variables in grades that require them.

runtime/mercury_float.c:
runtime/mercury_deep_copy_body.h:
runtime/mercury_construct.c:
runtime/mercury_memory_zones.c:
runtime/mercury_stm.c:
runtime/mercury_trace_base.c:
runtime/mercury_type_info.c:
	Delete unused local variables.

util/mdemangle.c:
	Delete an unused static global variable.

	Use fputs in place of fprintf in a couple of places in order
	to avoid warnings about format strings that are not string literals.

	Delete an unused function.

util/mkinit.c:
util/mkinit_erl.c:
	Delete unused local variables.