Extract ix86 dllimport implementation to mingw

Extract ix86 dllimport implementation to mingw

This patch extracts the ix86 implementation for expanding a SYMBOL
into its corresponding dllimport, far-address, or refptr symbol.  It
will be reused in the aarch64-w64-mingw32 target.  The implementation
is copied as is from i386/i386.cc with minor changes to follow to the
code style.

Also this patch replaces the original DLL import/export implementation
in ix86 with mingw.

2024-06-08  Evgeny Karpov <Evgeny.Karpov@microsoft.com>

	gcc/ChangeLog:
	* config.gcc: Add winnt-dll.o, which contains the DLL
	import/export implementation.
	* config/i386/cygming.h (SUB_TARGET_RECORD_STUB): Remove the
	old implementation. Rename the required function to MinGW.
	Use MinGW implementation for COFF and nothing otherwise.
	(GOT_ALIAS_SET): Likewise.
	* config/i386/i386-expand.cc (ix86_expand_move): Likewise.
	* config/i386/i386-expand.h (ix86_GOT_alias_set): Likewise.
	(legitimize_pe_coff_symbol): Likewise.
	* config/i386/i386-protos.h (i386_pe_record_stub): Likewise.
	* config/i386/i386.cc (is_imported_p): Likewise.
	(legitimate_pic_address_disp_p): Likewise.
	(ix86_GOT_alias_set): Likewise.
	(legitimize_pic_address): Likewise.
	(legitimize_tls_address): Likewise.
	(struct dllimport_hasher): Likewise.
	(GTY): Likewise.
	(get_dllimport_decl): Likewise.
	(legitimize_pe_coff_extern_decl): Likewise.
	(legitimize_dllimport_symbol): Likewise.
	(legitimize_pe_coff_symbol): Likewise.
	(ix86_legitimize_address): Likewise.
	* config/i386/i386.h (GOT_ALIAS_SET): Likewise.
	* config/mingw/winnt.cc (i386_pe_record_stub): Likewise.
	(mingw_pe_record_stub): Likewise.
	* config/mingw/winnt.h (mingw_pe_record_stub): Likewise.
	* config/mingw/t-cygming: Add the winnt-dll.o compilation.
	* config/mingw/winnt-dll.cc: New file.
	* config/mingw/winnt-dll.h: New file.