PR target/52790
	* config/i386/cygming.h (SUB_TARGET_RECORD_STUB): New sub-target macro.
	* config/i386/i386-protos.h (i386_pe_record_stub): Add new prototype.
	* config/i386/i386.c (legitimize_pe_coff_extern_decl): New static
	function.
	(legitimize_pe_coff_symbol): Likewise.
	(is_imported_p): New helper-function.
	(ix86_option_override_internal): Make MEDIUM_PIC the default code-model
	for Windows x64 targets.
	(ix86_expand_prologue): Optimize for pe-coff targets.
	(ix86_expand_split_stack_prologue): Adjust for pe-coff targets.
	(legitimate_pic_address_disp_p): Adjust for x64 pe-coff to support
	medium/large code-model.
	(legitimize_pic_address): Likewise.
	(legitimize_tls_address): Likewise.
	(ix86_expand_call): Likewise.
	(x86_output_mi_thunk): Likewise.
	(get_dllimport_decl): Add new beimport argument.
	(construct_plt_address): Don't assert for x64 pe-coff targets.
	* config/i386/i386.h (PIC_OFFSET_TABLE_REGNUM): Adjust for x64 pe-coff
	targets.
	(SYMBOL_FLAG_STUBVAR): New macro.
	(SYMBOL_REF_STUBVAR_P): Likewise.
	* config/i386/winnt.c (stub_list): New structure.
	(stub_head): New local variable.
	(i386_pe_record_stub): New function.
	(i386_pe_file_end): Emit refptr-stubs.

From-SVN: r197373