6l: pe fixes

R=rsc, brainman
CC=golang-dev
https://golang.org/cl/4182061

src/cmd/6l/pass.c

@@ -289,7 +289,7 @@ patch(void)
 			// a different method is used to access them.
 			if(p->from.type == D_INDIR+D_GS
 			&& p->to.type >= D_AX && p->to.type <= D_DI 
-			&& p->from.offset != 0x58) {
+			&& p->from.offset <= 8) {
 				q = appendp(p);
 				q->from = p->from;
 				q->from.type = D_INDIR + p->to.type;

src/cmd/ld/pe.c

@@ -500,6 +500,7 @@ asmbpe(void)
 		IMAGE_FILE_EXECUTABLE_IMAGE|IMAGE_FILE_DEBUG_STRIPPED;
 	if (pe64) {
 		fh.SizeOfOptionalHeader = sizeof(oh64);
+		fh.Characteristics |= IMAGE_FILE_LARGE_ADDRESS_AWARE;
 		set(Magic, 0x20b);	// PE32+
 	} else {
 		fh.SizeOfOptionalHeader = sizeof(oh);