stabs.c static state

stabs.c static state

Move all the function local static state variables to file scope,
in order to tidy memory on exit and to reinit everything for that
annoying oss-fuzz.  Also fix a couple memory leaks.

	* read.h (read_begin, read_end): Declare.
	* read.c (read_begin): Call stabs_begin.
	(read_end): Call stabs_end.
	* stabs.c (stabs_begin, stabs_end): New functions.
	(in_dot_func_p): Delete, use current_function_label instead.
	(cached_sec): Move from s_stab_generic.
	(last_asm_file, file_label_count): Move from generate_asm_file.
	(line_label_count, prev_lineno, prev_line_file): Move from
	stabs_generate_asm_lineno.
	(void_emitted_p): Move from stabs_generate_asm_func.
	(endfunc_label_count): Move from stabs_generate_asm_endfunc.
	(stabs_generate_asm_lineno): Simplify setting of
	prev_line_file.
	(stabs_generate_asm_func): Don't leak current_function_label.
	(stabs_generate_asm_endfunc): Likewise.