delete hack for interface equality now that it supported by the 6g compiler

R=rsc
DELTA=21  (0 added, 21 deleted, 0 changed)
OCL=17123
CL=17136

src/cmd/gc/sys.go

@@ -81,4 +81,3 @@ export func	stringtorune(string, int32) (int32, int32);	// convert bytes to rune
 
 export func	exit(int32);
 
-export func	BUG_intereq(a, b interface{}) bool;	// should not be necessary

src/cmd/gc/sysimport.c

@@ -69,6 +69,5 @@ char *sysimport =
 	"export func sys.bytestorune (? *sys.uint8, ? sys.int32, ? sys.int32) (? sys.int32, ? sys.int32)\n"
 	"export func sys.stringtorune (? sys.string, ? sys.int32) (? sys.int32, ? sys.int32)\n"
 	"export func sys.exit (? sys.int32)\n"
-	"export func sys.BUG_intereq (a interface { }, b interface { }) (? sys.bool)\n"
 	"\n"
 	"$$\n";

src/runtime/rt0_amd64.s

@@ -132,22 +132,3 @@ TEXT cas(SB), 7, $0
 	RET
 	MOVL	$1, AX
 	RET
-
-// func BUG_intereq(a, b interface{}) bool {
-//	return a == b
-// }
-// TODO: delete once 6g can compile a == b on interfaces.
-TEXT sys·BUG_intereq(SB),7,$0
-	// First interface at 8(SP) and 16(SP)
-	// Second interface at 24(SP) and 32(SP)
-	// Answer at 40(SP)
-	MOVQ 8(SP), AX
-	CMPQ AX, 24(SP)
-	JNE 6(PC)
-	MOVQ 16(SP), AX
-	CMPQ AX, 32(SP)
-	JNE 3(PC)
-	MOVQ $1, 40(SP)
-	RET
-	MOVQ $0, 40(SP)
-	RET