CLEANUP: qpack: suppress by default stdout traces

Remove the definition of DEBUG_HPACK on qpack-dec.c which forces the
QPACK decoding traces on stderr. Also change the name to use a dedicated
one for QPACK decoding as DEBUG_QPACK.
diff --git a/Makefile b/Makefile
index 9e861a2..0c511bc 100644
--- a/Makefile
+++ b/Makefile
@@ -257,7 +257,7 @@
 # DEBUG_MEM_STATS, DEBUG_DONT_SHARE_POOLS, DEBUG_FD, DEBUG_POOL_INTEGRITY,
 # DEBUG_NO_POOLS, DEBUG_FAIL_ALLOC, DEBUG_STRICT_ACTION=[0-3], DEBUG_HPACK,
 # DEBUG_AUTH, DEBUG_SPOE, DEBUG_UAF, DEBUG_THREAD, DEBUG_STRICT, DEBUG_DEV,
-# DEBUG_TASK, DEBUG_MEMORY_POOLS, DEBUG_POOL_TRACING.
+# DEBUG_TASK, DEBUG_MEMORY_POOLS, DEBUG_POOL_TRACING, DEBUG_QPACK.
 DEBUG = -DDEBUG_STRICT -DDEBUG_MEMORY_POOLS
 
 #### Trace options
diff --git a/src/qpack-dec.c b/src/qpack-dec.c
index ed43bae..166e1ae 100644
--- a/src/qpack-dec.c
+++ b/src/qpack-dec.c
@@ -35,9 +35,7 @@
 #include <haproxy/http-hdr.h>
 #include <haproxy/tools.h>
 
-#define DEBUG_HPACK
-
-#if defined(DEBUG_HPACK)
+#if defined(DEBUG_QPACK)
 #define qpack_debug_printf fprintf
 #define qpack_debug_hexdump debug_hexdump
 #else
@@ -207,7 +205,7 @@
 		if (efl_type == QPACK_LFL_WPBNM) {
 			/* Literal field line with post-base name reference */
 			uint64_t index __maybe_unused, length;
-			unsigned int n __maybe_unused, h;
+			unsigned int n __maybe_unused, h __maybe_unused;
 
 			qpack_debug_printf(stderr, "literal field line with post-base name reference:");
 			n = *raw & 0x08;