conf: add function to get child with default

src/conf.c

@@ -399,6 +399,19 @@ int ConfGetChildValue(const ConfNode *base, const char *name, const char **vptr)
     }
 }
 
+ConfNode *ConfGetChildWithDefault(const ConfNode *base, const ConfNode *dflt,
+    const char *name)
+{
+    ConfNode *node = ConfNodeLookupChild(base, name);
+    if (node != NULL)
+        return node;
+
+    /* Get 'default' value */
+    if (dflt) {
+        return ConfNodeLookupChild(dflt, name);
+    }
+    return NULL;
+}
 
 int ConfGetChildValueWithDefault(const ConfNode *base, const ConfNode *dflt,
     const char *name, const char **vptr)

src/conf.h

@@ -82,6 +82,7 @@ int ConfValIsFalse(const char *val);
 void ConfNodePrune(ConfNode *node);
 int ConfRemove(const char *name);
 
+ConfNode *ConfGetChildWithDefault(const ConfNode *base, const ConfNode *dflt, const char *name);
 ConfNode *ConfNodeLookupKeyValue(const ConfNode *base, const char *key, const char *value);
 int ConfGetChildValue(const ConfNode *base, const char *name, const char **vptr);
 int ConfGetChildValueInt(const ConfNode *base, const char *name, intmax_t *val);