MINOR: muxes: Add a flag to specify a multiplexer uses the HTX

A multiplexer must now set the flag MX_FL_HTX when it uses the HTX to structured
the data exchanged with channels. the muxes h1 and h2 set this flag. Of course,
for the mux h2, it is set on h2_htx_ops only.

include/types/connection.h

@@ -294,6 +294,7 @@ enum {
 enum {
 	MX_FL_NONE        = 0x00000000,
 	MX_FL_CLEAN_ABRT  = 0x00000001, /* abort is clearly reported as an error */
+	MX_FL_HTX         = 0x00000002, /* set if it is an HTX multiplexer */
 };
 
 /* xprt_ops describes transport-layer operations for a connection. They

src/mux_h1.c

@@ -2343,7 +2343,7 @@ static const struct mux_ops mux_h1_ops = {
 	.shutw       = h1_shutw,
 	.show_fd     = h1_show_fd,
 	.reset       = h1_reset,
-	.flags       = MX_FL_NONE,
+	.flags       = MX_FL_HTX,
 	.name        = "h1",
 };
 

src/mux_h2.c

@@ -5682,7 +5682,7 @@ static const struct mux_ops h2_htx_ops = {
 	.shutr = h2_shutr,
 	.shutw = h2_shutw,
 	.show_fd = h2_show_fd,
-	.flags = MX_FL_CLEAN_ABRT,
+	.flags = MX_FL_CLEAN_ABRT|MX_FL_HTX,
 	.name = "H2",
 };