add console emulation into serial terminal support using vt100-compatible escape sequences, add --enable-serial into configure, and fix some bugs in the support.

stage2/Makefile.in

@@ -109,7 +109,8 @@ libgrub_a_SOURCES = boot.c builtins.c common.c char_io.c cmdline.c \
 
 libgrub_a_CFLAGS = $(GRUB_CFLAGS) -I$(top_srcdir)/lib \
 	-DGRUB_UTIL=1 -DFSYS_EXT2FS=1 -DFSYS_FAT=1 -DFSYS_FFS=1 \
-	-DFSYS_MINIX=1 -DFSYS_REISERFS=1 -fwritable-strings
+	-DFSYS_MINIX=1 -DFSYS_REISERFS=1 -DSUPPORT_SERIAL \
+	-fwritable-strings
 
 
 # Stage 2 and Stage 1.5's.
@@ -135,9 +136,14 @@ PRE_STAGE2_LINK = -nostdlib -Wl,-N -Wl,-Ttext -Wl,8200
 START_LINK = -nostdlib -Wl,-N -Wl,-Ttext -Wl,8000
 NBLOADER_LINK = -nostdlib -Wl,-N -Wl,-Ttext -Wl,0
 PXELOADER_LINK = -nostdlib -Wl,-N -Wl,-Ttext -Wl,7C00
-@NETBOOT_SUPPORT_TRUE@STAGE2_COMPILE = @NETBOOT_SUPPORT_TRUE@$(STAGE2_CFLAGS) -fno-builtin -nostdinc \
-@NETBOOT_SUPPORT_TRUE@	-I$(top_srcdir)/netboot -DSUPPORT_NETBOOT=1
-@NETBOOT_SUPPORT_FALSE@STAGE2_COMPILE = @NETBOOT_SUPPORT_FALSE@$(STAGE2_CFLAGS) -fno-builtin -nostdinc
+@NETBOOT_SUPPORT_TRUE@NETBOOT_FLAGS = @NETBOOT_SUPPORT_TRUE@-I$(top_srcdir)/netboot -DSUPPORT_NETBOOT=1
+@NETBOOT_SUPPORT_FALSE@NETBOOT_FLAGS = 
+@SERIAL_SUPPORT_TRUE@SERIAL_FLAGS = @SERIAL_SUPPORT_TRUE@-DSUPPORT_SERIAL=1
+@SERIAL_SUPPORT_FALSE@SERIAL_FLAGS = 
+
+STAGE2_COMPILE = $(STAGE2_CFLAGS) -fno-builtin -nostdinc \
+	$(NETBOOT_FLAGS) $(SERIAL_FLAGS)
+
 
 STAGE1_5_LINK = -nostdlib -Wl,-N -Wl,-Ttext -Wl,2000
 STAGE1_5_COMPILE = $(STAGE2_COMPILE) -DNO_DECOMPRESSION=1 -DSTAGE1_5=1