opts: change write_symbols to support bitmasks

opts: change write_symbols to support bitmasks

To support multiple debug formats, we need to move away from explicit
enumeration of each individual combination of debug formats.

gcc/c-family/ChangeLog:

	* c-opts.c (c_common_post_options): Adjust access to debug_type_names.
	* c-pch.c (struct c_pch_validity): Use type uint32_t.
	(pch_init): Renamed member.
	(c_common_valid_pch): Adjust access to debug_type_names.

gcc/ChangeLog:

	* common.opt: Change type to support bitmasks.
	* flag-types.h (enum debug_info_type): Rename enumerator constants.
	(NO_DEBUG): New bitmask.
	(DBX_DEBUG): Likewise.
	(DWARF2_DEBUG): Likewise.
	(XCOFF_DEBUG): Likewise.
	(VMS_DEBUG): Likewise.
	(VMS_AND_DWARF2_DEBUG): Likewise.
	* flags.h (debug_set_to_format): New function declaration.
	(debug_set_count): Likewise.
	(debug_set_names): Likewise.
	* opts.c (debug_type_masks): Array of bitmasks for debug formats.
	(debug_set_to_format): New function definition.
	(debug_set_count): Likewise.
	(debug_set_names): Likewise.
	(set_debug_level): Update access to debug_type_names.
	* toplev.c: Likewise.

gcc/objc/ChangeLog:

	* objc-act.c (synth_module_prologue): Use uint32_t instead of enum
	debug_info_type.

gcc/testsuite/ChangeLog:

	* gcc.dg/pch/valid-1.c: Adjust diagnostic message in testcase.
	* lib/dg-pch.exp: Adjust diagnostic message.