jtag/drivers/remote_bitbang: use sizeof to determine maximum unix socket path length

Different *nix systems use different constants, so sizeof should be
used instead. This fixes the build on OS X (as sun_path length is
hardcoded to 104 on Darwin).

Change-Id: I1df611383dedcfc6d153ec59b453a895c7d84e94
Reported-by: Xiaofan Chen <xiaofanc@gmail.com>
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/2095
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-by: Xiaofan <xiaofanc@gmail.com>

src/jtag/drivers/remote_bitbang.c

@@ -29,10 +29,6 @@
 #include <jtag/interface.h>
 #include "bitbang.h"
 
-#ifndef UNIX_PATH_LEN
-#define UNIX_PATH_LEN 108
-#endif
-
 /* arbitrary limit on host name length: */
 #define REMOTE_BITBANG_HOST_MAX 255
 
@@ -192,8 +188,8 @@ static int remote_bitbang_init_unix(void)
 
 	struct sockaddr_un addr;
 	addr.sun_family = AF_UNIX;
-	strncpy(addr.sun_path, remote_bitbang_host, UNIX_PATH_LEN);
-	addr.sun_path[UNIX_PATH_LEN-1] = '\0';
+	strncpy(addr.sun_path, remote_bitbang_host, sizeof(addr.sun_path));
+	addr.sun_path[sizeof(addr.sun_path)-1] = '\0';
 
 	if (connect(fd, (struct sockaddr *)&addr, sizeof(struct sockaddr_un)) < 0) {
 		LOG_ERROR("connect: %s", strerror(errno));