Is codec_info_defaults useful?

If it is useful:
- Make it const in addition to static, use uppercase for const values.
- No need to initialise a struct with static storage, it is implictly
  initialised to zero of the appropriate type.

include/blosc2.h

@@ -108,12 +108,12 @@ extern "C" {
     do {                                            \
         if ((pointer) == NULL) {                    \
             BLOSC_TRACE_ERROR("Pointer is null");   \
-            return rc;                              \
+            return (rc);                            \
         }                                           \
     } while (0)
 #define BLOSC_ERROR(rc)                             \
     do {                                            \
-        int rc_ = rc;                               \
+        int rc_ = (rc);                             \
         if (rc_ < BLOSC2_ERROR_SUCCESS) {           \
             char *error_msg = print_error(rc_);     \
             BLOSC_TRACE_ERROR("%s", error_msg);     \

include/blosc2/codecs-registry.h

@@ -11,8 +11,6 @@
 #ifndef BLOSC_BLOSC2_CODECS_REGISTRY_H
 #define BLOSC_BLOSC2_CODECS_REGISTRY_H
 
-#include "blosc2.h"
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -45,9 +43,6 @@ typedef struct {
     char *decoder;
 } codec_info;
 
-// Silence unused codec_info typedef warning
-static codec_info codec_info_defaults BLOSC_ATTRIBUTE_UNUSED = {0};
-
 #ifdef __cplusplus
 }
 #endif