altos: ao_packet_getchar needs to return 'int' so AO_READ_AGAIN works

With ao_packet_getchar returning 'char', AO_READ_AGAIN would get
converted to 0xff instead of -1 on return, making ao_packet_echo
either produce a bogus character on output, breaking command
responses, or wedge and never exit when the link was dropped.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/drivers/ao_packet_master.c b/src/drivers/ao_packet_master.c
index 23545049..42a4f5bf 100644
--- a/src/drivers/ao_packet_master.c
+++ b/src/drivers/ao_packet_master.c
@@ -17,7 +17,7 @@
 
 #include "ao.h"
 
-static char
+static int
 ao_packet_getchar(void)
 {
 	int c;