CLEANUP: qpack: move encoded macros to qpack-t.h to avoid duplication

QPACK_LFL_WLN_BIT and related encoded field line bitmasks were defined
in both qpack-enc.c and qpack-dec.c. Moved them to qpack-t.h where
they are shared between encoder and decoder, eliminating the duplicate
definitions.

Should be backported to ease any further commit to come.

include/haproxy/qpack-t.h

@@ -43,6 +43,14 @@
 #define QPACK_DEC_INST_SCCL     0x40 // Stream Cancellation
 #define QPACK_DEC_INST_SACK     0x80 // Section Acknowledgment
 
+/* Encoded field line bitmasks (shared between encoder and decoder) */
+#define QPACK_EFL_BITMASK   0xf0
+#define QPACK_LFL_WPBNM     0x00 // Literal field line with post-base name reference
+#define QPACK_IFL_WPBI      0x10 // Indexed field line with post-based index
+#define QPACK_LFL_WLN_BIT   0x20 // Literal field line with literal name
+#define QPACK_LFL_WNR_BIT   0x40 // Literal field line with name reference
+#define QPACK_IFL_BIT       0x80 // Indexed field line
+
 /* RFC 9204 6. Error Handling */
 enum qpack_err {
 	QPACK_ERR_DECOMPRESSION_FAILED = 0x200,

src/qpack-dec.c

@@ -44,14 +44,6 @@
 #define qpack_debug_hexdump(...) do { } while (0)
 #endif
 
-/* Encoded field line bitmask */
-#define QPACK_EFL_BITMASK  0xf0
-#define QPACK_LFL_WPBNM    0x00 // Literal field line with post-base name reference
-#define QPACK_IFL_WPBI     0x10 // Indexed field line with post-based index
-#define QPACK_LFL_WLN_BIT  0x20 // Literal field line with literal name
-#define QPACK_LFL_WNR_BIT  0x40 // Literal field line with name reference
-#define QPACK_IFL_BIT      0x80 // Indexed field line
-
 /* reads a varint from <raw>'s lowest <b> bits and <len> bytes max (raw included).
  * returns the 64-bit value on success after updating buf and len_in. Forces
  * len_in to (uint64_t)-1 on truncated input.

src/qpack-enc.c

@@ -1,6 +1,7 @@
 #include <haproxy/qpack-enc.h>
 
 #include <haproxy/buf.h>
+#include <haproxy/qpack-t.h>
 #include <haproxy/intops.h>
 
 /* Returns the byte size required to encode <i> as a <prefix_size>-prefix
@@ -265,8 +266,6 @@ int qpack_encode_field_section_line(struct buffer *out)
 	return 0;
 }
 
-#define QPACK_LFL_WLN_BIT  0x20 // Literal field line with literal name
-
 /* Encode a header in literal field line with literal name.
  * Returns 0 on success else non-zero.
  */