Ignore line continuation when escaped as \\, from Simon Nicolussi.

cfg.c

@@ -109,6 +109,8 @@ load_cfg(const char *path, struct cmd_ctx *ctxin, struct causelist *causes)
 		len = strlen(line);
 		if (len > 0 && line[len - 1] == '\\') {
 			line[len - 1] = '\0';
+			/* Ignore escaped backslash at EOL. */
+			if (len > 1 && line[len - 2] != '\\')
 				continue;
 		}
 		buf = line;

tmux.1

@@ -493,7 +493,8 @@ Multiple commands may be specified together as part of a
 .Em command sequence .
 Each command should be separated by spaces and a semicolon;
 commands are executed sequentially from left to right and
-lines ending with a backslash continue on to the next line.
+lines ending with a backslash continue on to the next line,
+except when escaped by another backslash.
 A literal semicolon may be included by escaping it with a backslash (for
 example, when specifying a command sequence to
 .Ic bind-key ) .