re PR c++/72813 (atomic header cannot be compiled into translation unit with -fkeep-inline-functions)

	PR c++/72813
	* gcc.c (default_compilers): Don't add -o %g.s for -S -save-temps
	of c-header.

	* c-decl.c (pop_file_scope): Set flag_syntax_only to 1 after writing
	PCH file.

	* decl2.c (c_parse_final_cleanups): Set flag_syntax_only to 1 after
	writing PCH file.

From-SVN: r244328