Since we will be using calloc_str to put a string into it, convert the function to calloc_strcat which does it automatically.

cgminer.c

@@ -2308,8 +2308,7 @@ static bool submit_upstream_work(struct work *work, CURL *curl, bool resubmit)
 
 		flip80(data, work->data);
 		header = bin2hex(data, 80);
-		gbt_block = calloc_str(header);
+		gbt_block = calloc_strcat(header);
-		sprintf(gbt_block, "%s", header);
 		free(header);
 
 		if (work->gbt_txns < 0xfd) {

util.c

@@ -1479,7 +1479,7 @@ void dev_error(struct cgpu_info *dev, enum dev_reason reason)
 }
 
 /* Calloc enough memory to fit string s, rounding up to 4 byte alignment */
-void *calloc_str(char *s)
+void *calloc_strcat(char *s)
 {
 	size_t len = strlen(s);
 	void *ptr = NULL;
@@ -1493,6 +1493,8 @@ void *calloc_str(char *s)
 	ptr = calloc(len, 1);
 	if (unlikely(!ptr))
 		quit(1, "Failed to calloc ptr in calloc_str");
+
+	sprintf(ptr, "%s", s);
 out:
 	return ptr;
 }

util.h

@@ -52,7 +52,7 @@ bool extract_sockaddr(struct pool *pool, char *url);
 bool auth_stratum(struct pool *pool);
 bool initiate_stratum(struct pool *pool);
 void dev_error(struct cgpu_info *dev, enum dev_reason reason);
-void *calloc_str(char *s);
+void *calloc_strcat(char *s);
 void *realloc_strcat(char *ptr, char *s);
 
 #endif /* __UTIL_H__ */