Add pseudoteletypewriter to emulator

https://justine.storage.googleapis.com/emulator628.mp4

tool/build/emucrt/emucrt.S

@@ -19,8 +19,6 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/macros.h"
 
-	cmpxchg	%ecx,(%rdx)
-
 	.section .start,"ax",@progbits
 emucrt:	bofram	9f
 	movslq	(%rsp),%rdi			# argc

tool/build/emucrt/emucrt.lds

@@ -22,7 +22,7 @@ ENTRY(_start)
 
 SECTIONS {
 
-  .text : {
+  .text IMAGE_BASE_VIRTUAL : {
     *(.start)
     KEEP(*(.initprologue))
     KEEP(*(SORT_BY_NAME(.init.*)))

tool/build/emucrt/emucrt.mk

@@ -5,7 +5,7 @@ PKGS += TOOL_BUILD_EMUCRT
 
 TOOL_BUILD_EMUCRT =					\
 	o/$(MODE)/tool/build/emucrt/emucrt.o		\
-	tool/build/emucrt/emucrt.lds
+	o/$(MODE)/tool/build/emucrt/emucrt.lds
 
 .PHONY: o/$(MODE)/tool/build/emucrt
 o/$(MODE)/tool/build/emucrt:				\