let slug_count returns -1 if error occurs

src/node.c

@@ -571,13 +571,8 @@ node * r3_tree_insert_pathl_ex(node *tree, const char *path, int path_len, route
     // common prefix not found, insert a new edge for this pattern
     if ( prefix_len == 0 ) {
         // there are two more slugs, we should break them into several parts
-        char *err = NULL;
+        int slug_cnt = slug_count(path, path_len, errstr);
-        int slug_cnt = slug_count(path, path_len, &err);
+        if (slug_cnt == -1) {
-        if (err) {
-            if(errstr) {
-                *errstr = err;
-            }
-            free(err);
             return NULL;
         }
 

src/slug.c

@@ -172,7 +172,7 @@ int slug_count(const char * needle, int len, char **errstr) {
         if (errstr) {
             asprintf(errstr, "Incomplete slug pattern. PATTERN (%d): '%s', OFFSET: %ld, STATE: %d", len, needle, p - needle, state);
         }
-        return 0;
+        return -1;
     }
     return cnt;
 }

src/str.c

@@ -11,6 +11,7 @@
 #include <assert.h>
 #include "r3.h"
 #include "r3_str.h"
+#include "slug.h"
 #include "zmalloc.h"
 
 int r3_pattern_to_opcode(const char * pattern, int len) {