Revert the entry point label to 'start' to unbreak the build.

Pointy hat to:	jhb

sys/boot/i386/zfsboot/Makefile

@@ -57,7 +57,7 @@ zfsboot1: zfsldr.out
 	objcopy -S -O binary zfsldr.out ${.TARGET}
 
 zfsldr.out: zfsldr.o
-	${LD} ${LDFLAGS} -e main -Ttext ${ORG1} -o ${.TARGET} zfsldr.o
+	${LD} ${LDFLAGS} -e start -Ttext ${ORG1} -o ${.TARGET} zfsldr.o
 
 CLEANFILES+=	zfsboot2 zfsboot.ld zfsboot.ldr zfsboot.bin zfsboot.out \
 		zfsboot.o zfsboot.s zfsboot.s.tmp sio.o cons.o drv.o util.o

sys/boot/i386/zfsboot/zfsldr.S

@@ -34,7 +34,7 @@
 		.set SIZ_SEC,0x200		# Sector size
 
 		.set NSECT,0x80
-		.globl main
+		.globl start
 		.code16
 
 /*
@@ -46,7 +46,7 @@
  * Setup the segment registers to flat addressing (segment 0) and setup the
  * stack to end just below the start of our code.
  */
-main:		cld				# String ops inc
+start:		cld				# String ops inc
 		xor %cx,%cx			# Zero
 		mov %cx,%es			# Address
 		mov %cx,%ds			#  data