Rename main0 to main.

Makefile

@@ -60,7 +60,7 @@ kernel : $(OBJS) bootother.S initcode.S
 	$(LD) -N -e start -Ttext 0 -o initcode.out initcode.o
 	$(OBJCOPY) -S -O binary initcode.out initcode
 	$(OBJDUMP) -S initcode.o > initcode.asm
-	$(LD) -Ttext 0x100000 -e main0 -o kernel $(OBJS) -b binary initcode bootother
+	$(LD) -Ttext 0x100000 -e main -o kernel $(OBJS) -b binary initcode bootother
 	$(OBJDUMP) -S kernel > kernel.asm
 	$(OBJDUMP) -t kernel | awk '/SYMBOL TABLE/ { go=1; next } go {print $$1, $$NF}' >kernel.sym
 

defs.h

@@ -102,7 +102,7 @@ void            proc_exit(void);
 int             proc_kill(int);
 int             proc_wait(void);
 void            procdump(void);
-void            scheduler(void);
+void            scheduler(void) __attribute__((noreturn));
 void            setupsegs(struct proc*);
 void            sleep(void*, struct spinlock*);
 void            userinit(void);

initcode.S

@@ -4,6 +4,7 @@
 #include "traps.h"
 
 # exec(init, argv)
+.globl start
 start:
   pushl $argv
   pushl $init

main.c

@@ -10,8 +10,8 @@ extern char edata[], end[];
 void bootothers(void);
 
 // Bootstrap processor starts running C code here.
-void
-main0(void)
+int
+main(void)
 {
   int i;
   static volatile int bcpu;  // cannot be on stack